Electrophotographic image forming apparatus, developing apparatus, and coupling member

ABSTRACT

A developing device usable with an electrophotographic image forming apparatus, the apparatus including a driving shaft rotatable by a motor and having a rotating force applying portion, and a movable member, the developing device being mountable to the movable member, and the developing device being movable in a direction substantially perpendicular to an axial direction of the driving shaft in response to movement of the movable member in one direction with the developing device mounted to the movable member, the developing device includes i) a developing roller for developing an electrostatic latent image formed on an electrophotographic photosensitive drum, the developing roller being rotatable about an axis; and ii) a coupling member for transmitting a rotating force to the developing roller, the coupling member including, a rotating force receiving portion engageable with the rotating force applying portion to receive a rotating force from the driving shaft, and a rotating force transmitting portion for transmitting the rotating force received through the rotating force receiving portion to the developing roller, the coupling member being capable of taking a rotational force transmitting angular position for transmitting the rotational force for rotating the developing roller to the developing roller, a pre-engagement angular position which is taken before the coupling member is engaged with the rotating force applying portion and in which the coupling member is inclined away from the rotational force transmitting angular position, and a disengaging angular position which is taken for the coupling member to disengage from the driving shaft and in which the coupling member is inclined away from the rotational force transmitting angular position in a direction opposite to the pre-engagement angular position; wherein in response to a movement of the developing device when the movable member moves in the one direction, the coupling member moves from the pre-engagement angular position to the rotational force transmitting angular position to be opposed to the driving shaft, and wherein when the movable member makes a further movement in the one direction from a position where the coupling member is opposed to the driving shaft, in response to the further movement, the coupling member is disengaged from the driving shaft by moving from the rotational force transmitting angular position to the disengaging angular position.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to an electrophotographic image formingapparatus, a developing apparatus used in the electrophotographic imageforming apparatus, and a coupling member used in the electrophotographicimage forming apparatus.

Examples of the electrophotographic image forming apparatus include anelectrophotographic copying machine, an electrophotographic printer (alaser beam printer, an LED printer, etc.), and the like.

The developing apparatus (developing device) is mounted to a mainassembly of the electrophotographic image forming apparatus and developsan electrostatic latent image formed on an electrophotographicphotosensitive member.

The developing device includes a developing device of a fixed type usedin a state in which it is mounted and fixed to a main assembly of theelectrophotographic image forming apparatus and a developing device of adeveloping cartridge type in which a user can mount it to the mainassembly and can demount it from the main assembly.

With respect to the developing device of the fixed type, maintenance isperformed by a service person. On the other hand, with respect to thedeveloping device of the developing cartridge type, maintenance isperformed by the user by replacing a developing cartridge with anotherone.

In a conventional electrophotographic image forming apparatus, thefollowing constitution is known when an electrostatic latent imageformed on a drum-shaped electrophotographic photosensitive member(hereinafter referred to as a “photosensitive drum”) is developed.

In a Japanese Laid-Open Patent Application (JP-A) 2003-202727, a gear(gear 42Y) is provided to a developing device and is engaged with a gearprovided to a main assembly of the image forming apparatus. Then, arotating force of a motor provided to the main assembly is transmittedto a developing roller through the gear provided to the main assemblyand the gear provided to the main assembly. In this way, a method ofrotating the developing roller is known.

Further, a color electrophotographic image forming apparatus in which adeveloping rotary rotatable in state in which a plurality of developingdevices is mounted to the developing rotary is provided to a mainassembly of the apparatus (JP-A Hei 11-015265). In this apparatus, thefollowing cartridge for transmitting a rotating force from the apparatusmain assembly to the developing devices is known. Specifically, a mainassembly-side coupling (coupling 71) provided to the apparatus mainassembly and a developing device-side coupling (coupling gear 65) ofdeveloping devices (developing devices 6Y, 6M, 6C) mounted to adeveloping rotary (multi-color developing device 6) are connected,whereby a rotating force is transmitted from the apparatus main assemblyto the developing devices. When the main assembly-side coupling and thedeveloping device-side coupling are connected, the main assembly-sidecoupling is once retracted into the apparatus (by spring 74) so as notto hinder movement of the developing rotary. Then, the developing rotaryis moved, so that a predetermined developing device is moved in adirection in which the main assembly-side coupling is provided.Thereafter, the retracted main assembly-side coupling is moved towardthe developing device-side coupling by using a moving mechanism such asa solenoid and the like (solenoid 75, arm 76). In this manner, both ofthe couplings are connected to each other. Then, a rotating force of amotor provided to the main assembly is transmitted to a developingroller through the main assembly-side coupling and the developingdevice-side coupling. As a result, the developing roller is rotated.Such a method is known.

However, in the conventional cartridge described in JP-A 2003-202727, adriving connection portion between the main assembly and the developingdevice constitutes an engaging portion for a gear (gear 35) and a gear(gear 42Y). For this reason, it is difficult to prevent rotationnon-uniformity of the developing roller.

In the conventional cartridge described in JP-A Hei 11-015265, asdescribed above, the main assembly-side coupling (coupling 71) is onceretracted into the apparatus so as not to hinder the movement of thedeveloping device. Further, during the transmission of the rotatingforce, it is necessary to move the retracted main assembly-side couplingtoward the developing device-side coupling. Thus, it is necessary toprovide a mechanism for moving the main assembly-side coupling towardthe developing device-side to the apparatus main assembly. Further, forimage formation, a time required for movement of the main assembly-sidecoupling must be considered.

SUMMARY OF THE INVENTION

A principal object of the present invention is to provide a developingapparatus (developing cartridge) capable of solving the above-describedproblems of the conventional cartridges, an electrophotographic imageforming apparatus using the developing apparatus, and a coupling memberused in the developing apparatus.

Another object of the present invention is to provide a developingapparatus (developing cartridge) capable of engaging a coupling memberprovided to the developing apparatus (developing cartridge) with adriving shaft by moving the developing apparatus in a directionsubstantially perpendicular to an axial direction of the driving shafteven in the case where a main assembly is not provided with a mechanismfor moving a main assembly-side coupling member in the axial directionby a solenoid. The object of the present invention is also to provide anelectrophotographic image forming apparatus using the developingapparatus and the coupling member used in the developing apparatus.

Another object of the present invention is to provide a developingapparatus (developing cartridge) capable of engaging a driving shaftprovided to a main assembly of an electrophotographic image formingapparatus from a direction substantially perpendicular to an axialdirection of the driving shaft. The object of the present invention isalso to provide the electrophotographic image forming apparatus usingthe developing apparatus and a coupling member used in the developingapparatus.

Another object of the present invention is to provide a developingapparatus (developing cartridge) capable of smoothly rotating adeveloping roller compared with the case where driving connection of amain assembly and the developing apparatus is performed through gears.The object of the present invention is also to provide anelectrophotographic image forming apparatus using the developingapparatus and a coupling member used in the developing apparatus.

Another object of the present invention is to provide a developingapparatus (developing cartridge) capable of engaging with a drivingshaft provided to a main assembly of an electrophotographic imageforming apparatus from a direction substantially perpendicular to anaxial direction of the driving shaft and capable of smoothly rotating adeveloping roller. The object of the present invention is also toprovide the electrophotographic image forming apparatus using thedeveloping apparatus and a coupling member used in the developingapparatus.

Another object of the present invention is to provide a developingapparatus capable of mounting with and demounting from a driving shaftprovided to a main assembly of an electrophotographic image formingapparatus from a direction substantially perpendicular to an axialdirection of the driving shaft by movement of a moving member in onedirection. The object of the present invention is also to provide theelectrophotographic image forming apparatus using the developingapparatus and a coupling member used in the developing apparatus.

Another object of the present invention is to provide a developingapparatus capable of mounting with and demounting from a driving shaftprovided to a main assembly of an electrophotographic image formingapparatus from a direction substantially perpendicular to an axialdirection of the driving shaft by movement of a moving member in onedirection and capable of smoothly rotating a developing roller. Theobject of the present invention is also to provide theelectrophotographic image forming apparatus using the developingapparatus and a coupling member used in the developing apparatus.

Another object of the present invention is to provide a developingapparatus including a coupling member capable of taking a rotating forcetransmitting angular position for transmitting a rotating force from amain assembly of an electrophotographic image forming apparatus to adeveloping roller, a pre-engagement angular position at which thecoupling member is inclined from the rotating force transmitting angularposition and is in a state before being engaged with a rotating forceapplying portion, and a disengagement angular position at which thecoupling member is inclined from the rotating force transmitting angularposition in a direction opposite from the pre-engagement angularposition to be disengaged from the driving shaft. The object of thepresent invention is to provide the electrophotographic image formingapparatus using the developing apparatus and the coupling member used inthe developing apparatus.

According to the present invention, it is possible to provide adeveloping apparatus capable of engaging a coupling member provided tothe developing apparatus (developing cartridge) with a driving shaft bymoving the developing apparatus (developing cartridge) in a directionsubstantially perpendicular to an axial direction of the driving shafteven in the case where a main assembly is not provided with a mechanismfor moving a main assembly-side coupling member in the axial directionby a solenoid. According to the present invention, it is also possibleto provide an electrophotographic image forming apparatus using thedeveloping apparatus and the coupling member used in the developingapparatus.

Further, according to the present invention, it is possible to provide adeveloping apparatus capable of engaging a driving shaft provided to amain assembly of an electrophotographic image forming apparatus from adirection substantially perpendicular to an axial direction of thedriving shaft. According to the present invention, it is also possibleto provide the electrophotographic image forming apparatus using thedeveloping apparatus and a coupling member used in the developingapparatus.

Further, according to the present invention, it is possible to smoothlyrotate a developing roller compared with the case where drivingconnection of an apparatus main assembly and the developing apparatus isperformed through gears.

Further, according to the present invention, it is possible to provide adeveloping apparatus capable of engaging with a driving shaft providedto a main assembly of an electrophotographic image forming apparatusfrom a direction substantially perpendicular to an axial direction ofthe driving shaft and capable of smoothly rotating a developing roller.According to the present invention, it is also possible to provide theelectrophotographic image forming apparatus using the developingapparatus and a coupling member used in the developing apparatus.

Further, according to the present invention, it is possible to provide adeveloping apparatus capable of mounting with and demounting from adriving shaft provided to the apparatus main assembly from a directionsubstantially perpendicular to an axial direction of the driving shaftby movement of a moving member in one direction. According to thepresent invention, it is also possible to provide theelectrophotographic image forming apparatus using the developingapparatus and a coupling member used in the developing apparatus.

Further, according to the present invention, it is possible to provide adeveloping apparatus capable of mounting with and demounting from adriving shaft provided to the apparatus main assembly from a directionsubstantially perpendicular to an axial direction of the driving shaftby movement of a moving member in one direction and capable of smoothlyrotating a developing roller. According to the present invention, it isalso possible to provide the electrophotographic image forming apparatususing the developing apparatus and a coupling member used in thedeveloping apparatus.

Further, according to the present invention, it is possible to provide adeveloping apparatus including a coupling member capable of taking arotating force transmitting angular position for transmitting a rotatingforce from the apparatus main assembly to a developing roller, apre-engagement angular position at which the coupling member is inclinedfrom the rotating force transmitting angular position and is in a statebefore being engaged with a rotating force applying portion, and adisengagement angular position at which the coupling member is inclinedfrom the rotating force transmitting angular position in a directionopposite from the pre-engagement angular position to be disengaged fromthe driving shaft.

Further, according to the present invention, it is possible to engageand disengage a coupling member provided to a developing apparatus withrespect to a driving shaft provided to an apparatus main assembly from adirection substantially perpendicular to an axial direction of thedriving shaft by movement of a moving member in one direction.

Further, according to the present invention, it is possible to engageand disengage a coupling member provided to a developing apparatus withrespect to a driving shaft provided to an apparatus main assembly from adirection substantially perpendicular to an axial direction of thedriving shaft by movement of a moving member in one direction and alsopossible to smoothly rotate a developing roller.

Further, according to the present invention, even when a main assemblyis not provided with a mechanism for moving a main assembly-sidecoupling member for transmitting a rotational force to a developingroller in an axial direction of the coupling member by a solenoid, it ispossible to engage a coupling member provided to a developing apparatuswith a driving shaft by movement of a moving member. As a result,according to the present invention, it is possible to realize animprovement in image forming speed.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a developing cartridge according toan embodiment of the present invention.

FIG. 2 is a perspective view of the developing cartridge according tothe embodiment of the present invention.

FIG. 3 is a perspective view of the developing cartridge according tothe embodiment of the present invention.

FIG. 4 is a side sectional view of a main assembly of anelectrophotographic image forming apparatus according to an embodimentof the present invention.

FIG. 5 is a perspective view of a developing roller according to anembodiment of the present invention.

FIG. 6 is a perspective view and a longitudinal sectional view of acoupling according to an embodiment of the present invention.

FIG. 7 is a perspective view of a development supporting memberaccording to an embodiment of the present invention.

FIG. 8 is a perspective view of a coupling according to an embodiment ofthe present invention.

FIG. 9 is a sectional view of a side of the developing cartridgeaccording to an embodiment of the present invention.

FIG. 10 is an exploded view of a coupling member according to anembodiment of the present invention.

FIG. 11 is a longitudinal sectional view of the developing cartridgeaccording to an embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of the developing cartridgeaccording to the embodiment of the present invention.

FIG. 13 is a longitudinal sectional view of the developing cartridgeaccording to the embodiment of the present invention.

FIG. 14 is a perspective view of a coupling according to the embodimentof the present invention.

FIG. 15 is a perspective view of a rotary member (hereinafter called“rotary”) according to the embodiment of the present invention.

FIG. 16 is a perspective view of the rotary according to the embodimentof the present invention.

FIG. 17 is a perspective view of the rotary according to the embodimentof the present invention.

FIG. 18 shows a view, as seen from a side, of an apparatus main assemblyaccording to an embodiment of the present invention.

FIG. 19 shows a view of the apparatus main assembly according to theembodiment of the present invention, as seen from a side.

FIG. 20 shows a view of the apparatus main assembly according to theembodiment of the present invention, as seen from the side.

FIG. 21 is the Figure of the apparatus main assembly according to theembodiment of the present invention, as seen from the side.

FIG. 22 is a longitudinal sectional view showing the process ofengagement between the drive shaft and the coupling according to anembodiment of the present invention.

FIG. 23 is an exploded perspective view of the drive shaft and thecoupling according to the embodiment of the present invention.

FIG. 24 is an exploded perspective view of the drive shaft and thecoupling according to the embodiment of the present invention.

FIG. 25 is a perspective view showing the process of disengagement ofthe coupling from drive shaft according to the embodiment of the presentinvention.

FIG. 26 is the timing chart of the operations of an embodiment of thepresent invention.

FIG. 27 is a perspective view of a coupling according to an embodimentof the present invention.

FIG. 28 is a perspective view of the coupling according to theembodiment of the present invention.

FIG. 29 is a perspective view of a drive shaft according to anembodiment of the present invention.

FIG. 30 is a perspective view of a coupling according to the embodimentof the present invention.

FIG. 31 is a perspective view of the coupling according to theembodiment of the present invention.

FIG. 32 is a perspective view of a side of a developing cartridgeaccording to an embodiment of the present invention.

FIG. 33 is a partly sectional view of the developing cartridge and adevelopment shaft according to the embodiment of the present invention.

FIG. 34 is a longitudinal sectional view illustrating the take-outprocess of the developing cartridge according to the embodiment of thepresent invention.

FIG. 35 is a longitudinal sectional view illustrating the process ofengagement between the drive shaft and the coupling according to theembodiment of the present invention.

FIG. 36 is a perspective view of a development supporting memberaccording to an embodiment of the present invention.

FIG. 37 is a perspective view of a side of a developing cartridgeaccording to an embodiment of the present invention.

FIG. 38 is a perspective view illustrating the state of the engagementbetween the drive shaft and the coupling according to the embodiment ofthe present invention, and a longitudinal sectional view.

FIG. 39 is a perspective view of a development supporting memberaccording to the embodiment of the present invention.

FIG. 40 is a perspective view of a coupling according to an embodimentof the present invention.

FIG. 41 is a perspective view of a side of a developing cartridgeaccording to an embodiment of the present invention.

FIG. 42 is a perspective view and a longitudinal sectional viewillustrating a state of the engagement between the drive shaft and thecoupling in the embodiment of the present invention.

FIG. 43 is an exploded perspective view illustrating a state of mountingthe coupling to the development supporting member, in the embodiment ofthe present invention.

FIG. 44 is a perspective view of a coupling according to an embodimentof the present invention.

FIG. 45 is a longitudinal sectional view illustrating an engaged statebetween the development shaft and the coupling according to theembodiment of the present invention.

FIG. 46 is a longitudinal sectional view showing an engaged statebetween the drive shaft and the coupling according to the embodiment ofthe present invention.

FIG. 47 is a side view of a rotary flange according to an embodiment ofthe present invention.

FIG. 48 is a side view of the rotary flange according to the embodimentof the present invention.

FIG. 49 illustrates a locus of the coupling shown in FIG. 47 accordingto an embodiment of the present invention.

FIG. 50 is a sectional view of the drive shaft and the coupling of FIG.38 according to an embodiment of the present invention.

FIG. 51 is an illustration of a coupling according to an embodiment ofthe present invention.

FIG. 52 is a longitudinal sectional view illustrating a state before theengagement between the drive shaft and the coupling concerning anembodiment of the present invention.

FIG. 53 is a perspective view and a longitudinal sectional view of acoupling according to an embodiment of the present invention.

FIG. 54 is a perspective view of a coupling according to an embodimentof the present invention.

FIG. 55 is a longitudinal sectional view showing an engaged statebetween the drive shaft and the coupling according to the embodiment ofthe present invention.

FIG. 56 is a perspective view showing the process of engagement betweenthe drive shaft and the coupling according to the embodiment of thepresent invention.

FIG. 57 is a perspective view of a developing cartridge according to anembodiment of the present invention.

FIG. 58 is a perspective view of the developing cartridge according tothe embodiment of the present invention.

FIG. 59 is a perspective view illustrating a driving input gearaccording to an embodiment of the present invention.

FIG. 60 is a perspective view of a developing cartridge according to anembodiment of the present invention.

FIG. 61 is a perspective view and a longitudinal sectional view of acoupling according to an embodiment of the present invention.

FIG. 62 is an exploded longitudinal section of a coupling and a drivinginput gear according to an embodiment of the present invention.

FIG. 63 is an exploded perspective view of the coupling and the bearingmember according to the embodiment of the present invention.

FIG. 64 is a longitudinal sectional view of a developing cartridgeaccording to an embodiment of the present invention.

FIG. 65 is a longitudinal sectional view of a developing cartridgeaccording to an embodiment of the present invention.

FIG. 66 is a perspective view showing an engaged state of the developingroller gear and the coupling according to the embodiment of the presentinvention.

FIG. 67 is a longitudinal sectional view illustrating process ofengagement between the coupling and the drive shaft according to theembodiment of the present invention.

FIG. 68 is a perspective view of the drive shaft and the couplingaccording to an embodiment of the present invention.

FIG. 69 is a longitudinal sectional view illustrating the process of thedisengagement of the coupling from the drive shaft according to theembodiment of the present invention.

FIG. 70 is a perspective view of a developing cartridge according to anembodiment of the present invention.

FIG. 71 is a perspective view of a side of a developing cartridgeaccording to the embodiment of the present invention (the side plate ofthe cartridge is omitted).

FIG. 72 is a perspective view illustrating a driving input gearaccording to an embodiment of the present invention.

FIG. 73 is a side view of the apparatus main assembly according to theembodiment of the present invention.

FIG. 74 is a side view of an apparatus main assembly according to anembodiment of the present invention.

FIG. 75 is a sectional view of the apparatus main assembly according tothe embodiment of the present invention.

FIG. 76 is a perspective view and a longitudinal sectional viewillustrating the coupling according to an embodiment of the presentinvention.

FIG. 77 is a side view and a perspective view of a coupling according toan embodiment of the present invention.

FIG. 78 is a longitudinal sectional view illustrating the process ofengagement and process of disengagement between the drive shaft and thecoupling according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, a developing cartridge, an electrophotographic imageforming apparatus, and a coupling member according to the presentinvention will be described with reference to the drawings.

In the following embodiments, a developing cartridge of the type inwhich a user can mount and demount the developing cartridge with respectto an apparatus main assembly. However, the present invention is alsoapplicable to a developing device which is used in a state in which itis mounted and fixed to the main assembly.

Further, the present invention is specifically applicable to a singlecoupling member (e.g., those shown in FIGS. 6(a), 14(a 3), 28(c), 30 and77(b)), a developing device (developing cartridge) (e.g., those shown inFIGS. 2, 57 and 60), and an electrophotographic image forming apparatus(e.g., those shown in FIGS. 5 and 75).

Embodiment 1 (1) Brief Description of Developing Cartridge (DevelopingDevice)

First, with reference to FIGS. 1 to 4, a developing cartridge B as adeveloping device to which an embodiment of the present invention isapplied (hereinafter simply referred to as a “cartridge”) will bedescribed. FIG. 1 is a sectional view of the cartridge B. FIGS. 2 and 3are perspective views of the cartridge B. FIG. 4 is a sectional view ofa color electrophotographic image forming apparatus main assembly A(hereinafter referred to as an “apparatus main assembly”).

This cartridge B can be mounted to and demounted from a rotary Cprovided to the apparatus main assembly A by a user.

Referring to FIGS. 1 to 3, the cartridge B includes a developing roller110. The developing roller is rotated by receiving a rotating force fromthe apparatus main assembly A through a coupling mechanism describedlater during a developing function. In a developer accommodating frame114, a developer t of a predetermined color is accommodated. Thisdeveloper is fed to a developer chamber 113 a in a predetermined amountby rotation of a stirring member 116. The fed developer is supplied to asurface of the developing roller by rotation of a sponge-like developersupplying roller 115 in the developer chamber 113 a. This developer isformed in a thin layer by being supplied with electric charges bytriboelectric charge between a thin plate-like developing blade 112 andthe developing roller 110.

The developer formed in the thin layer on the developing roller 110 isfed to a developing position by rotation. By applying a predetermineddeveloping bias to the developing roller 110, an electrostatic latentimage formed on an electrophotographic photosensitive member(hereinafter referred to as a “photosensitive drum”) 107 is developed.That is, the electrostatic latent image is developed by the developingroller 110.

Further, developer which does not contribute to the development of theelectrostatic latent image, i.e., residual developer removing on thesurface of the developing roller 110 is removed by the developersupplying roller 115. At the same time, a fresh developer is supplied tothe surface of the developing roller 110 by the developer supplyingroller 115. In this manner, a developing operation is successivelyperformed.

The cartridge B includes a developing unit 119. The developing unit 119includes a developing device frame 113 and the developer accommodatingframe 114. The developing unit 119 further includes the developingroller 110, the developing blade 112, the developer supplying roller115, the developer chamber 113 a, the developer accommodating frame 14,and the stirring member 116.

The developing roller 110 is rotatable about an axial line L1.

Here, the developing cartridge B is mounted by the user to a developingcartridge accommodating portion 130A provided to a rotation selectingmechanism (developing rotary) C of the apparatus main assembly A. Atthis time, as described later, a driving shaft of the apparatus mainassembly A and a coupling member as a rotating driving forcetransmitting part of the cartridge B are connected to each other ininterrelation with such an operation that the cartridge B is positionedat a predetermined position (opposing portion to the photosensitivedrum) by the developing rotary (rotation selecting mechanism) C. Thus,the developing roller 110 and the like are rotated by receiving adriving force from the apparatus main assembly A.

(2) Description of Electrophotographic Image Forming Apparatus

With respect to FIG. 4, a color electrophotographic image formingapparatus using the developing cartridge B described will be described.In the following, description will be made by taking a color laser beamprinter as an example of the color electrophotographic image formingapparatus.

As shown in FIG. 4, a plurality of cartridges B (B1, B2, B3, B4)accommodating developers (toners) different in color is mounted to therotary C.

The mounting and demounting of the cartridge B with respect to therotary C are performed by the user. By rotating the rotary C, acartridge B accommodating a developer of a predetermined color isdisposed opposite to the photosensitive drum 107. Then, an electrostaticlatent image formed on the photosensitive drum 107 is developed. Thedeveloped image is transferred onto a recording material S. Thisdeveloping and transferring operation is performed for each of thecolors. As a result, a color image is obtained. Hereinbelow, specificdescription will be made. The recording material S is a material onwhich an image can be formed and include, e.g., paper, an OHP sheet, andthe like.

Referring to FIG. 4, the photosensitive drum 107 is irradiated withlight based on image information from an optical means 101. By thisirradiation, an electrostatic latent image is formed on thephotosensitive drum 107. The electrostatic latent image is developedwith a developer by the developing roller 110. The developer imageformed on the photosensitive drum 107 is transferred onto anintermediary transfer member.

Next, the developer image transferred onto an intermediary transfer belt104 a as the intermediary transfer member is transferred onto therecording material S by a second transfer means. Then, the recordingmaterial S onto which the developer image is transferred is conveyed toa fixing means 105 including a pressing roller 105 a and a heatingroller 105 b. The developer image transferred onto the recordingmaterial S is fixed on the recording material S. After the fixation, therecording material S is discharged on a tray 106.

An image forming step will be described more specifically.

In synchronism with rotation of the intermediary transfer belt 104 a,the photosensitive drum 107 is rotated counterclockwisely (FIG. 4).Then, a surface of the photosensitive drum 107 is electrically chargeduniformly by a charging roller 108. The surface of the photosensitivedrum 107 is irradiated with light depending on image information, e.g.,about a yellow image by the optical (exposure) means 101. Thus, a yellowelectrostatic latent image is formed on the photosensitive drum 107.

The exposure means 101 is constituted as follows. The exposure means 101irradiates the photosensitive drum 107 with high on the basis of theimage information read from an external device (not shown). As a result,the electrostatic latent image is formed on the photosensitive drum 107.The exposure means 101 includes a laser diode, a polygon mirror, ascanner motor, an imaging lens, and a reflection mirror.

From the unshown external device, an image signal is sent. By thisoperation, the laser diode emits light depending on the image signal andthe polygon mirror is irradiated with the light (as image light). Thepolygon mirror is rotated at a high speed by the scanner motor toreflect the image light, so that the surface of the photosensitive drum107 is selectively exposed to the image light through the imaging lensand the reflection mirror. As a result, the electrostatic latent imagedepending on the image information is formed on the photosensitive drum107.

Simultaneously with this electrostatic latent image formation, therotary C is rotated, whereby a yellow cartridge B1 is moved to adeveloping position. Then, a predetermined developing bias is applied tothe developing roller 110. As a result, a yellow developer is depositedon the electrostatic latent image, so that the electrostatic latentimage is developed with the yellow developer. Thereafter, a bias voltageof an opposite polarity to that of the developer is applied to apressing roller (a primary transfer roller) 104 j for the intermediarytransfer belt 104 a, so that the yellow developer image on thephotosensitive drum 107 is primary-transferred onto the intermediarytransfer belt 104 a.

As described above, after the primary transfer of the yellow developerimage is completed, the rotary C is rotated. As a result, a subsequentcartridge B2 is moved to be located at a position opposite to thephotosensitive drum 107. The above-described process is performed withrespect to a magenta cartridge B2, a cyan cartridge B3, and a blackcartridge B4. In this way, by repeating the process for each of magenta,cyan, and black, four color developer images are superposed on theintermediary transfer belt 104 a.

Incidentally, the yellow cartridge B1 accommodates the yellow developerand forms the yellow developer image. The magenta cartridge B2accommodates a magenta developer and forms a magenta developer image.The cyan cartridge B3 accommodates a cyan developer and forms a cyandeveloper image. The black cartridge B4 accommodates a black developerand forms a black developer image.

During the image formation described above, a secondary transfer roller104 b is in a noncontact state with the intermediary transfer belt 104a. A cleaning charging roller 104 f is also in a noncontact state withthe intermediary transfer belt 104 a.

After the four color developer images are formed on the intermediarytransfer belt 104 a, the secondary transfer roller 104 b is pressedagainst the intermediary transfer belt 104 a (FIG. 4). In synchronismwith the press contact of the secondary transfer roller 104 b, therecording material S waiting at a position in the neighborhood of aregistration roller pair 103 e is sent to a nip between the transferbelt 104 a and the transfer roller 104 b. At the same time, a recordingmaterial S is fed from a cassette 103 a by a feeding roller 103 b and aconveying roller pair 103 c as a feeding (conveying) means 103.

Immediately before the registration roller pair 103 e, a sensor 99 isdisposed. The sensor 99 detects a leading end of the recording materialS and stops the rotation of the registration roller pair 103 e, thusplacing the recording material S in a standby state at a predeterminedposition.

To the transfer roller 104 b, a bias voltage of an opposite polarity tothat of the developer is applied, so that the developer images on thetransfer belt 104 a are simultaneously secondary-transferred onto theconveyed recording material S.

The recording material S onto which the developer images are transferredand conveyed to the fixing means 105 through a conveying belt unit 103f. By the fixing means 105, fixation of the developer images isperformed. The recording material S subjected to the fixation isdischarged on a discharging tray 106 disposed at an upper portion of theapparatus main assembly by a discharging roller pair 103 g. In this way,formation of an image o the recording material S is completed.

After completion of the secondary transfer, the charging roller 104 f ispressed against the transfer belt 104 a, so that the surface of the belt104 a and the developer remaining on the surface of the belt 104 a aresupplied with the predetermined bias voltage. As a result, a residualelectric charge is removed.

The residual developer subjected to the charge removal iselectrostatically re-transferred from the belt 104 a onto thephotosensitive drum 107 through a primary transfer nip. As a result, thesurface of the belt 104 a is cleaned. The residual developerre-transferred onto the photosensitive drum 107 after the secondarytransfer is removed by a cleaning blade 117 a contacting thephotosensitive drum 107. The removed developer is collected din aresidual developer box 107 d through a conveying passage (not shown).

Incidentally, an accommodating portion 130 a is a chamber in which theabove-descried cartridge B is accommodated and is provided to the rotaryC at a plurality of positions. The rotary C is rotated in one directionin a state in which the cartridge B is mounted in the chamber. As aresult, a coupling member (described later) of the cartridge B isconnected to a driving shaft 180 provided to the apparatus main assemblyA and disconnected from the driving shaft 180. The cartridge B(developing roller 110) is moved in a direction substantiallyperpendicular to an axial line L3 direction of the driving shaft 180depending on the movement of the rotary C in one direction.

(3) Constitution of Developing Roller

Next, with reference to FIGS. 5(a) and 5(b), a constitution of thedeveloping roller 110 will be described. FIG. 5(a) is a perspective viewof the developing roller 110 as seen from a receiving side of a drivingforce from the main assembly A to the developing roller 110 (hereinaftersimply referred to as a “driving side”). FIG. 5(b) is a perspective viewof the developing roller 110 as seen from a side opposite from thedriving side with respect to the axial direction of the developingroller 110 (hereinafter referred to as a “non-driving side”).

The developing roller 110 includes a developing shaft 153 and a rubberportion 110 a. The developing shaft 153 is formed of anelectroconductive material such as iron or the like in an elongatedshaft shape and is covered with the rubber portion 110 a at a portionexcept for both end portions with respect to the axial direction. Thedeveloping shaft 153 is rotatably supported by the developing deviceframe 113 through bearings (not shown) at both end engaging portions 153d 1 and 153 d 2. Further, a cartridge 150 described later is positionedat an end portion 153 b on the driving side. The cartridge 150 isengaged with a rotating force transmitting pin 155 described later totransmit a driving force. The rubber portion 110 coaxially covers thedeveloping shaft 153. The rubber portion 110 carries the developer anddevelops the electrostatic latent image by application of a bias to thedeveloping shaft 153.

Nip width regulating members 136 and 137 are members for regulating anip width of the developing roller 110 with respect to thephotosensitive drum 107 at a constant value.

The unshown bearings are disposed at the both end portions 153 d 1 and153 d 2 of the developing roller 110 so as to support rotatably thedeveloping roller 110 on the developing device frame 113 (FIG. 1).

A developing gear (not shown) is disposed at the driving-side endportion 153 d 1 of the developing roller 110 and fixed to the developingshaft 153. The unshown developing gear transmits the rotating forcereceived from the apparatus main assembly A to the developing roller 110to other rotating members (e.g., the developer supplying roller 115, thestirring member, and the like) of the developing cartridge B.

Next, the driving-side end portion of the developing shaft 153 at whichthe cartridge 150 is movably (pivotably, swingably) mounted will bedescribed more specifically. The end portion 153 b has a spherical shapeso that the axial line L2 of the cartridge 150 (described later) can beinclined smoothly. In the neighborhood of an end of the developing shaft153, the driving force transmitting pin 155 for receiving the rotatingforce from the cartridge 150 is disposed in a direction crossing theaxial line L1 of the developing shaft 153.

The pin 155 as the rotating force transmitting portion is formed ofmetal and fixed to the developing shaft 153 by a method such as pressfitting, bonding, or the like. The fixing position may be any positionat which a driving force (rotating force) can be transmitted, i.e., adirection crossing the axial line L1 of the developing shaft (developingroller). It is desirable that the pin 155 passes through a sphericalcenter P2 (FIG. 10b ) of the end portion 153 b of the developing shaft153. This is because a transmission diameter of the rotating force isalways kept at a constant level even in the case where the axial line L1of the developing shaft 153 and the axial line L2 of the cartridge 150are somewhat deviated from each other. For this reason, it is possibleto realize stable rotating force transmission. The rotating forcetransmitting point may be provided at any positions. However, in orderto transmit a driving torque (rotating force) with reliability andimprove an assembly property, a single pin 155 is employed in thisembodiment. The pin 155 is passed through the center P2 of the endspherical surface 153 b. As a result, the pin 155 (155 a 1 and 155 a 2)is disposed so as to be projected at positions 180-degree opposite fromeach other at a peripheral surface of the driving shaft. That is, therotating force is transmitted a two points. In this embodiment, the pin155 is fixed at the end portion side within 5 mm from the end of thedrum shaft 153. However, the present invention is not limited thereto.

Incidentally, a main assembly-side developing electric contact (notshown) is disposed in the apparatus main assembly A so as to contact anon-driving-side end portion 153 c of the electroconductive developingshaft 153. An electric contact (not shown) of the developing cartridgeand the main assembly-side developing electric contact are brought intocontact with each other. In this way, a high-voltage bias is suppliedfrom the apparatus main assembly A to the developing roller 110.

(4) Description of Rotating Driving Force Transmitting Part (Coupling,Coupling Member)

An embodiment of the coupling (coupling member) which is a rotatingdriving force transmitting part as a principal constituent-element ofthe present invention will be described with reference to FIGS. 6(a) to6(f). FIG. 6(a) is a perspective view of the coupling as seen from theapparatus main assembly side and FIG. 6(b) is a perspective view of thecoupling as seen from the photosensitive drum side. FIG. 6(c) is a viewof the coupling as seen from a direction perpendicular to a direction ofa coupling rotating axis L2. FIG. 6(d) is a side view of the coupling asseen from the apparatus main assembly side and FIG. 6(e) is a view ofthe coupling as seen from the photosensitive drum side. FIG. 6(f) is asectional view of the coupling taken along S3-S3 line shown in FIG.6(d).

The developing cartridge B is detachably mounted to the cartridgeaccommodating portion 130 a in the rotary C provided in the apparatusmain assembly A. This mounting is performed by the user. The rotary C isrotationally driven and stopped at a position at which the cartridge Breaches a predetermined position (developing position at which thecartridge B is located opposite to the photosensitive drum 107). By thisoperation, the coupling (coupling member) 150 is engaged with a drivingshaft 180 provided to the apparatus main assembly A. Further, the rotaryC is rotated in one direction to move the cartridge B from thepredetermined position (developing position). That is, the cartridge Bis retracted from the predetermined position. As a result, the coupling150 is moved apart from the driving shaft 180. The coupling 150 receivesthe rotating force from a motor 64 (FIG. 17) provided to the apparatusmain assembly A in a state of engagement with the driving shaft 180. Thecoupling 150 transmits the rotating force to the developing roller 110.As a result, the developing roller 110 is rotated by the rotating forcereceived from the apparatus main assembly A.

As described above, the driving shaft 180 has a pin 182 (rotating forceapplying portion) and is rotated by the motor 64.

A material for the coupling 150 is a resin material such as polyacetal,polycarbonate, or the like. In order to enhance rigidity of the coupling150, it is also possible to enhance the rigidity by incorporating glassfiber or the like into the resin material depending on a load torque.Further, it is also possible to employ a metal material. Thus, thematerial for the coupling 150 may be appropriately selectable. However,the resin-made coupling can be easily processed, so that the respectivecartridges in this embodiment are formed of the resin material.

The coupling 150 mainly comprises three portions.

The first portion is engageable with the drive shaft 180 (which will bedescribed hereinafter) as shown in FIG. 6(c), and it is a driven portion150 a for receiving the rotational force from the rotational forcetransmitting pin 182 which is a rotational force applying portion (mainassembly side rotational force transmitting portion) provided on thedrive shaft 180. In addition, the second portion is engageable with thepin 155 provided to the developing device shaft 153, and it is a drivingportion 150 b for transmitting the rotational force to the developingroller 110. In addition, the third portion is an intermediate portion150 c for connecting the driven portion 150 a and the driving portion150 b with each other (FIGS. 8 (c) and (f)).

As shown in FIG. 6(f) the driven portion 150 a is provided with a driveshaft insertion opening portion 150 m which expands toward the rotationaxis L2. The driving portion 150 b has a developing device shaftinsertion opening portion 150 l.

The opening 150 m is defined by a conical driving shaft receivingsurface 150 f which expands toward the drive shaft 180 (FIGS. 9 to 13)side. The receiving surface 150 f constitutes a recess 150 z as shown inFIG. 6 (f). The recess 150 z includes the opening 150 m at a positionopposite from the developing roller 110 with respect to the direction ofthe axis L2.

By this, regardless of rotation phase of the developing roller 110 inthe cartridge B, the coupling 150 can move (pivot) among apre-engagement angular position (FIG. 22(a)), a rotational forcetransmitting angular position (FIG. 22(d)), and a disengaging angularposition (FIGS. 25(a) (d)) relative to the axis L3 of the drive shaft180 without being prevented by the free end portion 182 a of the driveshaft 180. The details thereof will be described hereinafter.

A plurality of projections (the engaging portions) 150 d (150 d 1-150 d4) are provided at equal intervals on a circumference about the axis L2on an end surface of the recess 150 z. Between the adjacent projections150 d, entrance portions 150 k (150 k 1, 150 k 2, 150 k 3, 150 k 4) areprovided. An interval between the adjacent projections 150 d 1-150 d 4is larger than the outer diameter of the pin 182, so that the rotationalforce transmitting pins provided to the drive shaft 180 (rotationalforce applying portions) 182 are received. The pins are the rotationalforce applying portions. The recesses between the adjacent projectionsare the entrance portions 150 k 1-150 k 4. When the rotational force istransmitted to the coupling 150 from the drive shaft 180, the pins 182are received by any of the entrance portions 150 k 1-150 k 4. Inaddition, in FIG. 6 (d), the rotational force reception surfaces(rotational force receiving portions) 150 e (150 e 1-150 e 4) areprovided in the upstream with respect to the clockwise direction (X1) ofeach projection 150 d. The receiving surface 150 e 1-150 e 4 is extendedin the direction crossing with the rotational direction of the coupling150. More particularly, the projection 150 d 1 has a receiving surface150 e 1, the projection 150 d 2 has a receiving surface 150 e 2, theprojection 150 d 3 has a receiving surface 150 e 3, and, a projection150 d 4 has a receiving surface 150 e 4. In the state where the driveshaft 180 rotates, the pin 182 a 1, 182 a 2 contacts to any of thereceiving surfaces 150 e. By doing so, the receiving surface 150 econtacted by the pin 182 a 1, 182 a 2 is pushed by the pin 182. By this,the coupling 150 rotates about the axis L2.

In order to stabilize the transmission torque transmitted to thecoupling 150 as much as possible, it is desirable to dispose therotational force receiving surfaces 150 e on a phantom circle (the samecircumference) that has a center O on the axis L2 (FIG. 6(d)). By this,the rotational force transmission radius is constant and the torquetransmitted to the coupling 150 is stabilized. In addition, as for theprojections 150 d, it is preferable that the position of the coupling150 is stabilized by the balance of the forces which the coupling 150receives. For that reason, in this embodiment, the receiving surfaces150 e are disposed at the diametrically opposed positions (180 degrees).More particularly, in this embodiment, the receiving surface 150 e 1 andthe receiving surface 150 e 3 are diametrically opposed relative to eachother, and the receiving surface 150 e 2 and the surface 150 e 4 arediametrically opposed relative to each other. By this arrangement, theforces which the coupling 150 receives constitute a force couple.Therefore, the coupling 150 can continue rotary motion only by receivingthe force couple. For this reason, the coupling 150 can rotate withoutthe necessity of being specified in the position of the rotation axis L2thereof. In addition, as for the number thereof, as long as the pins 182of the drive shaft 180 (the rotational force applying portion) can enterthe entrance portions 150 k(150 k 1-150 k 2), it is possible to selectsuitably. In this embodiment, as shown in FIG. 6, the four receivingsurfaces are provided. This embodiment is not limited to this example.For example, the receiving surfaces 150 e (projections 150 d 1-150 d 4)do not need to be disposed on the same circumference (the phantom circleC1 and FIG. 6(d)). Or, it is not necessary to dispose at thediametrically opposed positions. However, the effects described abovecan be provided by disposing the receiving surfaces 150 e as describedabove.

Here, in this embodiment, the diameter of the pin is approximately 2 mm,and a circumferential length of the entrance portion 150 k isapproximately 8 mm. The circumferential length of the entrance portion150 k is an interval between adjacent projections 150 d (on the phantomcircle). The dimensions are not limiting to the present invention.

Similarly to the opening 150 m, a developing device shaft insertionopening portion 150 l has a conical rotational force receiving surface150 i of an as an expanded part which expands toward the developingdevice shaft 153. The receiving surface 150 i constitutes a recess 150q, as shown in FIG. 6 (f).

By this, irrespective of the rotation phase of the developing roller 110in the cartridge B, the coupling 150 can move (pivot, swing) among arotational force transmitting angular position, a pre-engagement angularposition, and a disengaging angular position to the axis L1 withoutbeing prevented by the free end portion of the developing device shaft153. The recess 150 q is constituted in the illustrated example by aconical receiving surface 150 i which it has centering on the axis L2.The standby openings 150 g 1 or 150 g 2 (“opening”) are provided in thereceiving surface 150 i (FIG. 6(b)). As for the coupling 150, the pins155 can be inserted into the inside of this opening 150 g 1 or 150 g 2so that it may be mounted to the developing device shaft 153. And, thesize of the openings 150 g 1 or 150 g 2 is larger than the outerdiameter of the pin 155. By doing so, irrespective of the rotation phaseof the developing roller 110 in the cartridge B, the coupling 150 ismovable (pivotable, swingable) among the rotational force transmittingangular position and the pre-engagement angular position (or disengagingangular position) as will be described hereinafter without beingprevented by the pin 155.

More particularly, the projection 150 d is provided adjacent to the freeend of the recess 150 z. And, the projections (projection portions) 150d project in the intersection direction crossing with the rotationaldirection in which the coupling 150 rotates, and are provided with theintervals along the rotational direction. And, in the state where thecartridge B is mounted to the rotary C, the receiving surfaces 150 eengage to or abutted to the pin 182, and are pushed by the pin 182receiving the force from the rotating drive shaft.

By this, the receiving surfaces 150 e receive the rotational force fromthe drive shaft 180. In addition, the receiving surfaces 150 e aredisposed in equidistant from the axis L2, and constitute a pairinterposing the axis L2 they are constituted by the surface in theintersection direction in the projections 150 d. In addition, theentrance portions (recesses) 150 k are provided along the rotationaldirection, and they are depressed in the direction of the axis L2.

The entrance portion 150 k is formed as a space between the adjacentprojections 150 d. In the state where the cartridge B is mounted to therotary C in the case where the drive axis stops its rotation, the pin182 enters the entrance portion 150 k when the coupling engages with thedrive shaft 180. And, the pin 182 of the rotating drive shaft 180 pushesthe receiving surface 150 e. Or, in the case where the drive shaft 180has already rotated when the coupling engages with the drive shaft 180,the pin 182 enters the entrance portion 150 k and pushes the receivingportion 150 e.

By this, the coupling 150 rotates.

The rotational force receiving surface (rotational force receivingmember (portion)) 150 e may be disposed inside of the driving shaftreceiving surface 150 f. Or, the receiving surface 150 e may be providedin the portion outwardly projected from the receiving surface 150 f withrespect to the direction of the axis L2. When the receiving surface 150e is disposed inside of the receiving surface 150 f, the entranceportion 150 k is disposed inside of the receiving surface 150 f

More particularly, the entrance portion 150 k is the recess providedbetween the projections 150 d in the inside of the arc part of thereceiving surface 150 f. In addition, when the receiving surface 150 eis disposed at the position which outwardly projects, the entranceportion 150 k is the recess positioned between the projections 150 d.Here, the recess may be a through hole extended in the direction of theaxis L2, or it may be closed at one end thereof. More particularly, therecess is provided by the space region provided between the projection150 d. And, what is necessary is just to be able to enter the pin 182into the region in the state where the cartridge B is mounted to therotary C.

These structures of the standing-by portion apply similarly to theembodiments as will be described hereinafter.

In FIG. 6 (e), the rotational force transmission surfaces (therotational force transmitting portions) 150 h and (150 h 1 or 150 h 2)are provided in the upstream, with respect to the counterclockwisedirection (X2), of the opening 150 g 1 or 150 g 2. And, the rotationalforce is transmitted to the developing roller 110 from the coupling 150by the convection sections 150 h 1 or 150 h 2 contacting to the pins 155a 1, 155 a 2. More particularly, the transmitting surfaces 150 h 1 or150 h 2 push the side surface of the pin 155. By this, the coupling 150rotates with the center thereof aligned with the axis L2. Thetransmitting surface 150 h 1 or 150 h 2 is extended in the directioncrossing with the rotational direction of the coupling 150.

Similarly to the projection 150 d, it is desirable to dispose thetransmitting surfaces 150 h 1 or 150 h 2 diametrically opposed relativeto each other on the same circumference.

At the time of manufacturing the drum coupling member 150 with aninjection molding, the intermediate portion 150 c may become thin. Thisis because the coupling is manufactured so that the driving forcereceiving portion 150 a, the driving portion 150 b and the intermediateportion 150 c have a substantially uniform thickness. When the rigidityof the intermediate portion 150 c is insufficient, therefore, it ispossible to make the intermediate portion 150 c thick so that drivenportion 150 a, the driving portion 150 b, and the intermediate portion150 c have the substantially equivalent thickness.

(6) Shape of Supporting Member

The description will be made, referring to FIG. 7, about a supportingmember (mounting member) 157. FIG. 7 (a) is a perspective view, as seenfrom a drive shaft side, and FIG. 7 (b) is a perspective view, as seenfrom the developing roller side.

The supporting member 157 has functions of holding the coupling 150 andpositioning the cartridge B in the rotary C. Further, it has thefunction of supporting the coupling 150 so that the rotational force canbe transmitted to the developing roller 110.

More particularly, the supporting member 157 mounts the cartridge 150 tothe cartridge 150.

As shown in FIG. 7 the supporting member includes a guide 140L2 duringmounting and demounting of the cartridge B with respect to anaccommodating portion 130 a provided to the rotary C and a cylinder140L1 for positioning the cartridge B in the accommodating portion 130a. And, the coupling 150 described above is disposed in an inner space157 b of a cylinder portion 157 c provided coaxially with the developingroller (not shown). At an inner peripheral surface 157 i constitutingthe space 157 b, ribs 157 e 1 and 157 e 2 for retaining the coupling 150in the cartridge B are provided. The ribs 157 e 1 and 157 e 2 areprovided opposite to each other with respect to a movement direction X4of the cartridge B (rotational direction of the rotary C). Thesupporting member 157 is provided with positioning portions 157 d 1 and157 d 2 for fixing it to the developing device frame 113 and providedwith holes 157 g 1 or 157 g 2 which penetrate the fixing screw.

(6) Supporting Constitution of Coupling with Respect to Cartridge Frame

Referring to FIG. 8-FIG. 13, the description will be made as to thesupporting constitution (mounting constitution) of the developing roller110 and the coupling 150 with respect to the developing device frame(cartridge frame) 113. FIG. 8 is an enlarged view, as seen from thedriving side, of the major part around the developing roller of thecartridge. FIG. 9 is a sectional view taken along S4-S4 of FIG. 8. FIG.10 is a sectional view, taken along a developing axis L1, whichillustrate the state before mounting of the coupling and supportingmember. FIG. 11 is a sectional view which illustrates a state after themounting. FIG. 12 is a sectional view when the axis L2 of the couplingis substantially coaxially aligned with the axis L1 of the developingroller. FIG. 13 is a sectional view which illustrates a state afterrotating the coupling through 90 degrees from the state of FIG. 12. FIG.14 is a perspective view which illustrates the combined state of thedeveloping roller shaft and the coupling. FIG. 14(b 1)-(b 5) areperspective views, and FIG. 15(a 1)-(a 5) are views as seen from theaxis L1 direction.

As shown in FIG. 14 the coupling 150 is mounted so that the axis L2thereof can incline in any direction relative to the axis L1 of thedeveloping roller shaft 153 (developing roller).

In FIG. 14 (a 1) and FIG. 14 (b 1), the axis L2 of the coupling 150 isco-axial with the axis L1 of the developing roller 153. The state whenthe coupling 150 is inclined upward from this state is illustrated inFIG. 14 (a 2) and FIG. 14 (b 2). As shown in these figures, when theaxis L2 is inclined toward the opening 150 g side, the pin moves withinthe opening 150 g when these members are relatively viewed on the basisof the coupling. As a result, the coupling 150 is inclined about an axisAX (FIG. 12 (a 2)) perpendicular to the opening 150 a.

In FIG. 14 (b 3), the state where the coupling 150 is inclined rightwardis shown. As shown in this Figure, when the axis L2 inclines in theorthogonality direction of the opening 150 g, the pin rotates within theopening 150 g when these members are relatively viewed on the basis ofthe coupling. The axis of rotation is the axis AY (FIG. 14(a 3)) of thetransmission pin 155.

The states where the coupling 150 is inclined downward and leftward areshown in FIGS. 14(a 4) and (b 4) and FIGS. 14 (a 5) and (b 5),respectively. The coupling 150 inclined about each of the axes AX andAY.

In the directions different from the inclining direction described inthe foregoing, for example, at an intermediate position in theinclination direction in FIGS. 14 (a 2) and 14 (a 3), and at each ofintermediate positions in the inclination directions in FIGS. 14 (a 3)and 14 (a 4) and FIGS. 14 (a 5) and 14 (a 2), the inclination is made bycombining the rotations in the directions of the rotational axes AX andAY. Thus, the axis L2 can be pivoted in any direction relative to theaxis L1. At this time, the pin 155 is provided to the developing rollershaft 153. More particularly, the pin 155 projects from a peripheralsurface of the developing roller shaft 153. The coupling 150 disposedopposite to the pin 155 is provided with the opening 150 g. A size ofthe opening 150 g is set so that the pin does not interfere with the pinwhen the axis L2 inclined relative to the axis L1.

More particularly, the transmitting surface (rotational forcetransmitting portion) 150 h is movable relative to the pin (rotationalforce receiving portion) 155 (FIG. 14). The pin 155 has the transmittingsurface 150 in the movable condition. And, the transmitting surface 150h and the pin 155 are engaged to each other in the rotational directionof the coupling 150. Further, the gap is provided between thetransmitting surface 150 h and the pin 155. By this, the coupling 150 ismovable (pivotable, swingable) in all directions substantially relativeto the axis L1.

It has been mentioned that the axis L2 is slantable or inclinable in anydirection relative to the axis L1. However, the axis L2 does notnecessarily need to be linearly slantable to the predetermined angle inthe full range of 360-degree direction in the coupling 150. For example,the opening 150 g can be selected to be slightly wider in thecircumferential direction. By doing so, the time of the axis L2inclining relative to the axis L1, even if it is the case where itcannot incline to the predetermined angle linearly, the coupling 150 canrotate to a slight degree around the axis L2. Therefore, it can beinclined to the predetermined angle. In other words, the amount of theplay in the rotational direction of the opening 150 g is selectedproperly if necessary.

In this manner, the coupling 150 is revolvable or swingable over thefull-circumference substantially relative to the axis L1 of thedeveloping roller 110. More particularly, the coupling 150 is pivotableover the full-circumference thereof substantially relative to the drumshaft 153.

Furthermore, as will be understood from the foregoing explanation, thecoupling 150 is capable of whirling in and substantially over thecircumferential direction of the drum shaft 153. Here, the whirlingmotion is not a motion with which the coupling itself rotates about theaxis L2, but the inclined axis L2 rotates about the axis L1 of thedeveloping roller although the whirling here does not preclude therotation of the coupling per se about the axis L2 of the coupling 150.

It has been mentioned that the axis L2 is slantable or inclinable in anydirection relative to the axis L1. However, the axis L2 does notnecessarily need to be linearly slantable to the predetermined angle inthe full range of 360-degree direction in the coupling 150. For exampleand the opening 150 g can be selected to be slightly wider in thecircumferential direction. By doing so, the time of the axis L2inclining relative to the axis L1, even if it is the case where itcannot incline to the predetermined angle linearly and the coupling 150can rotate to a slight degree around the axis L2. Therefore, it can beinclined to the predetermined angle. In other words, the amount of theplay in the rotational direction of the opening 150 g is selectedproperly if necessary, in this manner and the coupling 150 is revolvableor swingable over the full-circumference substantially relative to drumshaft (rotational force receiving member) 153. More particularly and thecoupling 150 is pivotable over the full-circumference thereofsubstantially relative to the drum shaft 153, furthermore and as will beunderstood from the foregoing explanation, the coupling 150 is capableof whirling in and substantially over the circumferential direction ofthe drum shaft 153. Here and the whirling motion is not a motion withwhich the coupling itself rotates about the axis 12 and but the inclinedaxis L2 rotates about the axis L1 of the photosensitive drum andalthough the whirling here does not preclude the rotation of thecoupling per se about the axis L2 of the coupling 150.

In addition, the range movable in all directions substantially is therange in which when the user mounts the cartridge B to the apparatusmain assembly A, the coupling can move to the rotational forcetransmitting angular position irrespective of the phase of the driveshaft having the rotational force applying portion. In addition, it isthe range in which, in disengaging the coupling from the drive shaft,the coupling can move to the disengaging angular position irrespectiveof the stop angle phase of the drive shaft.

In addition, the coupling is provided with a gap between the rotationalforce transmitting portion (rotational force transmitting surface 150 h,for example), and the rotational force transmitting portion and therotational force receiving portion (pin 155, for example) to engage, sothat it is pivotable in all directions substantially relative to theaxis L1. In this manner, the coupling is mounted to the end of thecartridge B. For this reason, the coupling is the movable substantiallyin all directions relative to the axis L1.

This structure is similar in the embodiments of the coupling as will bedescribed hereinafter.

The assemblying processes will be described.

After mounting the developing roller 110 rotatably to the developingdevice frame 113, the pin 155 is mounted to the development shaft 153.Thereafter, the development gear 145 is assembled to the developmentshaft 153.

Thereafter, as shown in FIG. 10, the coupling 150 and the supportingmember 157 are inserted in the direction X3. First, the driving portion150 b is inserted toward the direction X3 downstream, while maintainingthe axis L2 of the coupling 150 in parallel with X3. At this time, thephase of the pin 155 of the development shaft 153 and the phase of theopening 150 g of the coupling 150 are matched with each other, and thepin 155 is made inserted into the openings 150 g 1 or 150 g 2. And, thefree end portion 153 b of the development shaft 153 is abutted to thereceiving surface 150 i the coupling 150. The free end portion 153 b ofthe development shaft 153 is the spherical surface and the receivingsurface 150 i the coupling 150 is a conic surface. Therefore, thedriving portion 150 b side of the coupling 150 is positioned to thecenter (the center of the spherical surface) of the free end portion 153b of the development shaft 153. As will be described hereinafter, whenthe coupling 150 rotates by the transmission of the driving force(rotational force) from the apparatus main assembly A, the pin 155positioned in the opening 150 g will be contacted to the rotationalforce transmission surfaces 150 h 1 or 150 h 2 and (FIG. 6b ). By this,the rotational force can be transmitted. Thereafter, one 157 w of theend of surfaces of the supporting member 157 is inserted downstream withrespect to the direction X3. By this, a part of coupling 150 is receivedin the space portion 157 b of the supporting member 157. And, thesupporting member 157 is fixed in the developing frame 113, thus, anintegral developing cartridge B is established.

The dimensions of the various portions of the coupling 150 will bedescribed. As shown in FIG. 10 (c), a maximum outer diameter of thedriven portion 150 a of the coupling 150 is ΦD2, a maximum outerdiameter of the driving portion 150 b is ΦD1, and a small diameter ofthe opening 150 g is ΦD3. In addition, a maximum outer diameter of thepin 155 is ΦD5, and an inner diameter of the retention rib 157 e of thesupporting member 157 is ΦD4. Here, the maximum outer diameter is theouter diameter of a maximum rotation locus about the rotational axis L1of the developing roller 110. The maximum outer diameters ΦD1, and ΦD3relating to the coupling 150 are the outer diameter of maximum rotationlocus about the axis L2. At this time, since ΦD5<ΦD3 is satisfied, thecoupling 150 can be assembled to the predetermined position by thestraight mounting operation in the direction X3 therefore, theassembling property is high. The diameter of the inner surface ΦD4 ofthe retention rib 157 e of the bearing member 157 is larger than ΦD2 ofthe coupling 150, and smaller than ΦD1 (ΦD2<ΦD4<ΦD1). By this, just thestep attached to the direction X3 straight is sufficient to assemble thesupporting member 157 to the predetermined position. For this reason,the assembling property can be improved (the state after the assembly isshown in FIG. 11).

As shown in FIG. 11, the retention rib 157 e of the supporting member157 is disposed closely to a flange portion 150 j of the coupling 150 inthe direction of the axis L1. More specifically, in the direction of theaxis L1, the distance from an end surface 150 j 1 of the flange portion150 j to the axis of the pin 155 is n1. In addition, the distance froman end surface 157 e 1 of the rib 157 e to the other end surface 157 j 2of the flange portion 150 j is n2. The distance n2<distance n1 issatisfied.

In addition, with respect to the direction perpendicular to the axis L1,the flange portion 150 j and the ribs 157 e 1, 157 e 2 are disposed sothat they are overlapped relative to each other. More specifically, thedistance n4 (amount of the overlapping) from the inner surface 157 e 3of the rib 157 e to the outer surface 150 j 3 of the flange portion 150j is the overlap amount n4 with respect to the orthogonality directionof the axis L1.

By such settings, the pin 155 is prevented from disengaging from theopening 150 g. That is, the movement of the coupling 150 is limited bythe bearing member 157. Thus, the coupling 150 does not disengage fromthe cartridge. The prevention of disengagement can be accomplishedwithout additional parts. The dimensions described above are desirablefrom the standpoint of reduction of manufacturing and assemblying costs.However, the present invention is not limited to these dimensions.

As described above FIGS. 9, 11 and 12, the receiving surface 150 i whichis the recess 150 q of the coupling 150 is in contact with the free endsurface 153 b of the development shaft 153 which is the projection.Therefore, the coupling 150 is swung along the free end portion (thespherical surface) 153 b about the center P2 of the free end portion(the spherical surface) 153 b in other words, the axis L2 is movablesubstantially in all directions irrespective of the phase of the drumshaft 153. The axis L2 of the coupling 150 is movable (pivotable,revolvable, movable) in all directions substantially. As will bedescribed hereinafter, in order that the coupling 150 may engage withthe drive shaft 180, the axis L2 is inclined toward the downstream withrespect to the rotating direction of the rotary C relative to the axisL1, just before the engagement. In other words, as shown in FIG. 17, theaxis L2 inclines so that the driven portion 150 a of the coupling 150positions at the downstream side with respect to the rotationaldirection X4 of the rotary.

The still more detailed description will be made.

As shown in FIG. 12, a distance n3 between a maximum outer diameter partand supporting member 157 of the driving portion 150 b the coupling 150is selected so that a slight gap is provided between them. By this, thecoupling 150 is pivotable.

As shown in FIG. 7, the ribs 157 e 1 and 157 e 2 are semi-circular ribsextending in parallel with the axis L1. The ribs 157 e 1 and 157 e 2 areperpendicular to the rotational direction X4.

In addition, a distance n2 (FIG. 11) in the direction of the axis L1from the rib 157 e to the flange portion 150 j is shorter than adistance n1 from the center of the pin 155 to the driving portion 150 bside edge. By this, the pin 155 does not disengage from the openings 150g 1 and 150 g 1.

Therefore, as shown in FIG. 9, the driven portion 150 a is greatlypivotable in the direction X4 relative to the axis L2 the coupling 150.In other words, the driving portion 150 b is greatly pivotable towardthe side not provided with the rib 150 e (perpendicular to the sheet ofthe drawing). FIG. 9 illustrates the state after the axis L2 isinclined. In addition, the coupling 150 can also be movable to the statesubstantially parallel to the axis L1 as shown In FIG. 12 from the stateof the inclined axis L2 as shown in FIG. 9. In this manner, the ribs 157e 1 and 157 e 2 are disposed. By doing so, the axis L2 of the coupling150 can be made pivotable relative to the axis L1, and in addition, thedeveloping frame and 13 can be prevented from disengaging from thecoupling 150. Both of the effects can be provided.

The coupling 150 has a play (the distance n2) in the direction of theaxis L1 relative to the development shaft 153. Therefore, the receivingsurface 150 i (the conic surface) may not always contact snuggly thedrum shaft free end portion 153 b (the spherical surface). In otherwords, the center of the pivoting may deviate from the center ofcurvature P2 of the spherical surface. However, even in such a case, theaxis L2 is rotatable or pivotable relative to the axis L1. For thisreason, the purpose of this embodiment can be accomplished.

In addition, maximum possible inclination angle α (FIG. 9) between theaxis L1 and the axis L2 is limited to one half of the taper angle (α1,FIG. 6(f)) between the axis L2 and the receiving surface 150 i. The apexangle of the conical shape of the receiving surface 150 i the coupling150 can be properly selected. By doing so, the inclination angle α 4 ofthe coupling 150 are set to the optimal value. The shape of the columnarportion 153 a of the development shaft 153 may be simply cylindrical. Bythis, the manufacturing cost can be saved.

The width of the opening 150 g in the standby state is selected so thatthe pin 155 may not interfere when the axis L2 inclines, as describedhereinbefore.

The locus of the flange portion 150 j when the driven portion 150 a sideinclines in the direction X5 is illustrated by the region T1 in FIG. 13.As shown in the Figure, even if the coupling 150 inclines, theinterference with the pin 155 does not occur, and therefore, the flangeportion 150 j can be provided over the full-circumference of thecoupling 150 (FIG. 6(b)). In other words, the shaft receiving surface150 i has conical shape, and therefore, when the coupling 150 inclines,the pin 155 does not enter in the region T1. For this reason, thecutting away range of the coupling 150 is minimized. Therefore, therigidity of the coupling 150 can be assured.

(7) Description of Constitution of Rotary (Moving Member, RotationSelecting Mechanism) of Apparatus Main Assembly

Next, with reference to FIGS. 15 to 21, a constitution of the rotary Cas the moving member will be described. FIGS. 15 and 16 are perspectiveviews of the rotary C in a state in which the developing cartridge B isnot mounted. FIG. 17A is a perspective view showing a state in which asingle developing cartridge B is mounted to the rotary C. FIGS. 18 to 21are side views showing the rotary C, the photosensitive drum 107, adriving train, and the developing cartridge B.

In the axial line L1 direction, rotary flanges 50L and 50R are providedat both end portions. Outside the rotary flanges 50L and 50R in theaxial line L1 direction, rotary side plates 54L and 54R are provided,respectively. The rotary flanges 50L and 50R and a central shaft 51thereof are rotatably supported by the side plates 54L and 54R locatedoutermostly in the axial line L1 direction.

At opposing surfaces 50Lb and 50Rb of the pair of flanges 50L and 50R,groove-like main assembly guides 130L1, 130L2, 130L3, 130L4, 130R1,130R2, 130R3, and 130R4 used during mounting and demounting of thecartridge B with respect to the rotary C (accommodating portion 130A)are provided. Along these main assembly guides provided to the apparatusmain assembly A, cartridge-side guides 140R1, 140R2, 140L1, and 140L2(FIGS. 2 and 3) of the cartridge B are inserted. That is, the cartridgeB is mountable to and demountable from the rotary C. The cartridge B isdetachably mounted to the rotary C by the user.

More specifically, at one end of the cartridge B (B1) with respect to alongitudinal direction of the cartridge B (B1), the guides 140R1 and140R2 are provided. Further, at the other longitudinal end of thecartridge B (B1), the guides 140L1 and 140L2 are provided. The userholds the cartridge B and inserts the guides 140R1 and 140R2 into theguide 130R1 provided to the rotary C. Similarly, the user inserts theguides 140L1 and 140L2 into the guide 130L1 provided to the rotary C. Inthis way, the cartridge B is detachably mounted to the accommodatingportion 130A provided to the rotary C by the user. That is, thecartridge B is guided by the above-described guides and is mounted toand demounted from the accommodating portion 130A with respect to adirection crossing the longitudinal direction of the cartridge B(developing roller 110). The cartridge B is mounted in a direction inwhich the longitudinal direction intersects a rotational direction X4 ofthe rotary C. Therefore, the cartridge B (coupling) provided at onelongitudinal end of the cartridge B is moved in a directionsubstantially perpendicular to the driving shaft 180 by rotation of therotary C. The cartridge B mounted to the rotary C is liable to rotateabout arcuate guides 140R1 and 140L1 when a rotating force istransmitted from the apparatus main assembly A to the cartridge B.However, elongated guides 140R2 and 140L2 contact inner surfaces ofgrooves of the guides 130R1 and 130 L1, so that the cartridge B ispositional with respect to the rotary C. That is, the cartridge B isdetachably accommodated in the accommodating portion 130A.

Similarly, the cartridge B (B2) is guided by the guides 130R2 and 130L2provided to the rotary C and detachably mounted to the accommodatingportion 130A. The cartridge B (B3) is guided by the guides 130R3 and130L3 provided to the rotary C and detachably mounted to theaccommodating portion 130A. The cartridge B (B4) is guided by the guides130R4 and 130L4 provided to the rotary C and detachably mounted to theaccommodating portion 130A.

That is, the cartridge B is detachably accommodated by the user in theaccommodating portion 130A provided to the rotary C.

FIG. 17 shows a state in which the developing cartridge B is mounted inthe apparatus main assembly 4 (rotary C).

Each of the developing cartridges B is positioned with respect to therotary C and is rotated by rotation of the rotary C. At this time, thedeveloping cartridge B is fixed to the rotary C by an urging spring, alock, or the like (not shown) so that a position of the developingcartridge B is not deviated by the rotation of the rotary C.

To the other rotary side plate 54L, a driving mechanism for rotating thedeveloping roller (not shown) is provided. That is, a developing devicedriving gear 181 engages with a pinion 65 fixed to a motor shaft of themotor 64. When the motor starts rotation, a rotating force istransmitted to the gear 181. The driving shaft 180 coaxially disposedwith the gear 181 starts rotation. As a result, the rotating force ofthe driving shaft 180 is transmitted to the developing roller 110 andthe like through the coupling 150. Incidentally, in this embodiment, thedriving shaft 180 has started rotation before the engagement of thecoupling 150. However, timing of the start of rotation of the drivingshaft 180 can be appropriately selectable.

The cartridge B rotates together with the pair of rotary flanges 50L and50R. That is, the rotary C stops its rotation when it is rotated apredetermined angle. As a result, the cartridge B is positioned at aposition (developing position) opposite to the photosensitive drum 107provided to the apparatus main assembly A. The coupling 150 engages withthe driving shaft 180 substantially simultaneously with the positioningand stop of the cartridge B. That is, a recess 1502 covers an end of anend portion 180 b of the driving shaft 180.

The driving shaft 180 has the substantially same constitution as theabove-described developing shaft. That is, the driving shaft 180includes a spherical end portion 180 b and a pin 182 penetrating analmost center of a principal portion 180 a of its cylindrical shape. Bythis pin 182, a rotating force (driving force) is transmitted to thecartridge B through the coupling 150.

To the rotary C, the four color cartridges B are mounted. Here, pressureapplication of the cartridges B to the photosensitive drum 107 isperformed in the following manner.

As described above, the flanges 50L and 50R are rotatably supported bythe rotary side plates 54L and 54R. The rotary side plates 54L and 54Rat both ends are positioned and fixed to side plates (not shown of theapparatus main assembly A through a swingable shaft 60 rotatablydisposed above the rotary side plates 54L and 54R. In other words, thecartridge B, the rotary flanges 50, and the rotary side plates 54 areintegrally swung about the swingable shaft 60. That is, integralswinging movement of the cartridge B and the rotary C is performed. As aresult, the cartridge B is pressed against or separated from thephotosensitive drum 107.

This pressing and separating operation performed by pressing up a rotarystay 66 disposed between the rotary side plates 54L and 54R by rotationof a cam (not shown).

Further, as described with reference to FIG. 15, the driving shaft 180is positioned and mounted at a predetermined position of the apparatusmain assembly A with respect to a radial direction and an axialsubstantially. Further, the cartridge B is also positioned at apredetermined position of the apparatus main assembly A by stop of therotation of the rotary C. These positioned driving shaft 180 andcartridge B are connected by the coupling 150. The coupling 150 isswingable (pivotable, movable) with respect to the cartridge B (frame).Accordingly, even between the driving shaft 180 positioned at thepredetermined position and the cartridge B positioned at thepredetermined position, the coupling 150 is capable of transmitting therotating force smoothly. That is, even when there is some shaft (axis)deviation between the driving shaft 180 and the cartridge 150, thecoupling 150 can smoothly transmit the rotating force.

This is one of remarkable effects of the embodiment of the coupling towhich the present invention is applied.

(8) Switching Constitution of Developing Cartridge (Developing Device)

At each of the outer peripheral surfaces of the flanges 50L and 50R, agear 50 a is integrally provided as shown in FIGS. 15 to 17. A pair ofidler gears 59L and 59R engaged with these gears 50 a is disposed atboth longitudinal end portions. These idler gears 59L and 59R areconnected by the swingable shaft 60. When the flange 50L disposed at oneof the longitudinal ends is rotated, the other flange 50R is rotated inphase through the gears 59L and 59R. By employing such a drivingconstitution, during the rotation of the rotary C or the rotation of thedeveloping roller 110, torsion of either one of the flanges 50L and 50Ris prevented.

With the gears 59L and 59R connected to the swinging center of therotary side plates 54L and 54R, i.e., the swingable shaft 60, a rotarydriving gear 65 engages. This gear 65 is connected to the motor 61. To arotating shaft of the motor 61, an encoder 62 is mounted. The encoder 62detects an amount of rotation of the motor 61 and controls the number ofrotation. Further, at an outer peripheral surface of one flange 50L, aflag 57 projected from the flange 50L in a radial direction is provided(FIG. 16). The flange 50L and the flag 57 are rotated so as to passthrough a photo-interruptor 58 fixed to the side plate 58. By detectingblocking of the photo-interruptor with the flag 57, the rotary C iscontrolled so as to rotate every predetermined angle. That is, after therotary C rotates a predetermined angle from the time when the flag 57blocks the photo-interruptor, the first developing cartridge stops at aposition opposite to the photosensitive drum 107. The rotary C isfurther rotated a predetermined angle in one direction and thereafterthe second developing cartridge stops at a position opposite to thephotosensitive drum 107. By repeating this operation four times in total(stops of the four color developing cartridges), a color image isformed.

That is, the cartridge B is moved in a direction perpendicular to theaxial line L3 of the driving shaft 180 by the rotate of the rotary C inone direction in a state in which the cartridge B is mounted to therotary C.

At an upper surface of the apparatus main assembly A, an opening formounting and demounting the developing cartridge B by the user and anopenable/closable cover 40 (FIG. 4) for covering the opening areprovided. Further, a door switch (not shown) for detecting theopen/close of the cover 40 is provided. A rotation operation of therotary C is started during electric power on and when the cover 40 isclosed (when the door switch is turned on).

(9) Positioning Constitution of Developing Cartridge (Developing Device)During Switching Operation

Operations of the rotary C and the cartridge B will be described step bystep with reference to FIGS. 18 to 21. For ease of description, only onecartridge in the rotary is shown.

First, in a state shown in FIG. 18, the cartridge B does not reach apredetermined position (the coupling member 150 is located at apre-rotation angular position). When the rotary C (is revolved in adirection of X4, the flag 57 partially projected from the outerperipheral surface of the rotary flange 50 described above reaches thephoto-interruptor 58, so that the rotary C stops at a predeterminedposition (a state shown in FIG. 19). At this time, the driving shaft 180and the coupling 150 of the cartridge B are connected to each other (thecoupling member 150 is located at a rotating force transmitting angularposition). The developing roller 110 is placed in a rotatable state. Inthis embodiment, the driving shaft 180 has already been rotated in astate in which the coupling 150 starts engagement with the driving shaft180. For this reason, the developing roller 110 is rotated. However, inthe case where the driving shaft 180 is stopped in a state in which thecoupling 150 is engaged with the driving shaft 180, the coupling 150waits in the rotatable state. The engagement (connection) of thecoupling 150 with the driving shaft 180 will be described later indetail.

Then, as described above, the cam (not shown) is actuated to contact therotary stay 66, so that the rotary C is moved counterclockwisely aboutthe swingable shaft 60. That is the developing roller 110 contacts thephotosensitive drum 107 by being moved in an X1 direction (a state ofFIG. 20). Then, a predetermined image forming operation is performed.

When the image forming operation is completed, the rotary C is rotatedin a clockwise direction about the swingable shaft 60 by a force of aspring (not shown). Thus, the rotary C is restored to the state shown inFIG. 19. That is, the developing roller 110 is moved apart from thephotosensitive drum 107 (the coupling member 150 is located at adisengagement angular position).

Then, the rotary C is rotated about the central shaft 51 in the X4direction so that a subsequent cartridge B can reach the developingposition (a state of FIG. 21). At this time, the connection between thedriving shaft 180 and the coupling 150 is released. That is, thecoupling 150 is disconnected from the driving shaft 180. The operationat this time will be specifically described later.

The above-described operations from the operation described withreference to FIG. 18 to the operation described with reference to FIG.21 are repeated four times in total for four colors, so that color imageformation is effected.

(10) Engaging Operation/Rotational Force Transmission/DisengagingOperation, of the Coupling

As has been described in the foregoing, immediately before the cartridgeB stops at the predetermined position of the apparatus main assembly A,or substantially simultaneously therewith, the coupling 150 is engagedwith the drive shaft 180. (From FIG. 18 to FIG. 19). And, when thecartridge B moves from the predetermined position of the apparatus mainassembly after the rotation during the predetermined period, thecoupling 150 is disengaged from the drive shaft 180 (from FIG. 20 toFIG. 21).

Referring to FIG. 22-FIG. 25, the description will be made with respectto the engaging operation, the rotational force transmitting operationand the disengaging operation of the coupling. FIG. 22 is a longitudinalsectional view illustrating the drive shaft, the coupling, and thedevelopment shaft. FIG. 23 is a longitudinal sectional view illustratingthe phase difference among the drive shaft, the coupling, and thedevelopment shaft. FIG. 25 is a longitudinal sectional view illustratingthe drive shaft, the coupling, and the development shaft.

In the process in which the cartridge B moves to the developing positionby the rotation of the rotary C, the coupling 150 is positioned at thepre-engagement angular position. More particularly, the axis L2 of thecoupling is beforehand inclined relative to the axis L1 of thedevelopment shaft 153 so that the driven portion 150 a positionsdownstream of the rotary rotational direction X4. By this inclination ofthe coupling 150, a downstream free end position 150A1 of the rotary Cwith respect to the rotational direction X4 thereof is positioned at thedevelopment shaft 153 side beyond a drive shaft free-end 180 b 3 withrespect to the direction of the axis L1. In addition, an upstream freeend position 150A2 with respect to the direction X4 is positioned at thepin 182 side beyond the drive shaft free-end 180 b 3 in the direction ofthe axis L1 (FIG. 22 (a), (b)). Here, the free end position is theposition nearest to the drive shaft with respect to the direction of theaxis L2 of the driven portion 150 a of the coupling 150 shown in FIGS. 6(a) and (c), and it is the remotest position from the axis L2. In otherwords, it is an edge line of the driven portion 150 a of the coupling150, or an edge line of the driven projection 150 d depending on therotation phase of the coupling (150A in FIGS. 6 (a) and (c)).

First, the downstream free end position 150A1 with respect to the rotaryrotational direction (X4) passes by the shaft free-end 180 b 3. And,after the coupling 150 passes the drive shaft 180, the receiving surface150 f or the projection 150 d of conical shape of the coupling 150contacts to the free end portion 180 b or the pin 182 of the drive shaft180. And, it inclines in response to the rotation of the rotary C sothat the axis L2 becomes parallel to the axis L1 (FIG. 22 (c)). And,finally, the position of the cartridge B is determined relative to theapparatus main assembly A. More particularly, the rotary C stops. Underthe present circumstances, the drive shaft 180 and the development shaft153 are substantially co-axial with each other. More particularly, thecoupling 150 is moved from the pre-engagement angular position to therotational force transmitting angular position so as to permit the freeend position 150A1 thereof to circumvent the drive shaft 180 (pivotingand swinging). And, the coupling 150 is inclined from the pre-engagementangular position toward the rotational force transmitting angularposition where the axis L2 is substantially co-axial with the axis L1.And, the coupling 150 and the drive shaft 180 are engaged with eachother (FIG. 22 (d)). More particularly, the recess 150 z covers the freeend portion 180 b. By this, the rotational force is enabled to be stablytransmitted from the drive shaft 180 to the coupling 150. In addition,at this time, the pin 152 is in the opening 150 g (FIG. 6 (b)), and thepin 182 is in the entrance portion 150 k.

In this embodiment, when the coupling 150 starts the engagement with thedrive shaft 180, the drive shaft 180 is already rotating. For thisreason, the coupling 150 begins the rotation immediately. However, whenthe drive shaft 180 is at rest at the time of the engagement with thedrive shaft 180 of the coupling 150, the coupling member 150 stands bywith the rotatable state, when the pin 182 is present in the entranceportion 150 k.

As has been described hereinbefore, according to this embodiment, thecoupling 150 is pivotable relative to the axis L1. Therefore, thecoupling 150 can be engaged relative to the drive shaft 180correspondingly to the rotation of the rotary C by the coupling 150 perse inclining, without interfering with the drive shaft 180 (coupling).

Furthermore, the engaging operation of the coupling 150 described aboveis possible regardless of the phase difference between the drive shaft180 and the coupling 150. Referring to FIG. 14 and FIG. 23, thedescription will be made as to the phase difference between the couplingand the drive shaft. FIG. 23 illustrates the phases of the coupling andthe drive shaft. In FIG. 23 (a), the pin 182 and the driving shaftreceiving surface 150 f of the coupling 150 oppose relative to eachother in the upstream with respect to the rotational direction X4 of therotary. In FIG. 23 (b), the pin 182 and the projection 150 d of thecoupling 150 oppose relative to each other. In FIG. 23 (c), the free endportion 180 b of the drive shaft and the projection 150 d of thecoupling 150 oppose relative to each other. In FIG. 23 (d), the free endportion 180 b and the receiving surface 150 f of the coupling opposerelative to each other. As shown in FIG. 14, the coupling 150 is mountedpivotably in all the directions relative to the development shaft 153.For this reason, as shown in FIG. 23, the coupling 150 is pivotable inthe mounting direction X4 irrespective of the phase of the developmentshaft 153 with respect to the rotational direction X4. In addition, thedownstream free end position 150A1 is positioned in the developingroller 110 side from the drive shaft free-end 180 b 3 in the rotationaldirection not related irrespective of the phase difference between thedrive shaft 180 and the coupling 150. In addition, the inclination angleof the coupling 150 is set so that the upstream free end position 150A2positions in the pin 182 side beyond the drive shaft free-end 180 b 3 inthe rotational direction X4. With such a setting, the downstream freeend position 150A1 in the rotational direction X4 passes by the driveshaft free-end 180 b 3 in response to the rotating operation of therotary C. And, in the case of FIG. 23 (a), the driving shaft receivingsurface 150 f contacts to the pin 182. In the case of FIG. 23 (b), theprojection 150 d contacts to the pin 182. In the case of FIG. 23 (c),the projection 150 d contacts to the free end portion 180 b. In the caseof FIG. 23 (d), the receiving surface 150 f contacts to the free endportion 180 b. In addition, the axis L2 approaches to the position inparallel with the axis L1 by the contact force (urging force) producedwhen the rotary C rotates, and they engage with each other (coupling).For this reason, irrespective of the phase difference between the driveshaft 180 and the coupling 150 or between the coupling 150 and thedevelopment shaft 153, they can engage with each other.

Referring to FIG. 24, the rotational force transmitting operation in thecase of the rotation of the developing roller 110 will be described. Thedrive shaft 180 rotates together with the gear (helical gear) 181 in thedirection of X8 in the Figure by the rotational force received from themotor 64. And, the pins 182 integral with the drive shaft 180 contact toany of the rotational force receiving surfaces 150 e 1-150 e 4 of thecoupling 150. By this, the coupling 150 rotates. The coupling 150further rotates. By this, the rotational force transmitting surface 150h 1 or 150 h 2 of the coupling 150 contacts to the pin 155 integral withthe development shaft 153. Then, the rotational force of the drive shaft180 rotates the developing roller 110 through the coupling 150 and thedevelopment shaft 153.

In addition, the free end portion 153 b of the development shaft 153 iscontacted to the receiving surface 150 i. The free end portion 180 b ofthe drive shaft 180 is contacted to the receiving surface 150 f. Bythis, the coupling 150 is positioned correctly (FIG. 22d ). Moreparticularly, the coupling 150 is positioned to the drive shaft 180 bythe recess 150 z covering the free end portion 180. At this time, evenif the axis L3 and the axis L1 are somewhat non-coaxial with each other,the coupling 150 can rotate without applying the large load to thedevelopment shaft 153 and the drive shaft 180 by the small inclinationof the coupling 150. For this reason, even if the drive shaft 180 andthe development shaft 153 deviate from each other by slight positiondeviation of the cartridge B due to the rotation of the rotary C, thecoupling 150 can transmit the rotational force smoothly.

This is one of the remarkable effects according to an embodiment of thecoupling of the present invention.

Referring to FIG. 25, the description will be made about the disengagingoperation of the coupling 150 from the drive shaft 180 in response tothe movement of the cartridge B from the predetermined position(developing position) by the rotary C rotating in the one direction.

First, the position of each of the pin 182 at the time of the cartridge(B) moving from the predetermined position will be described. After theimage formation finishes, as will be apparent from the foregoingdescription, the pin 182 is positioned at any two of the entering orentrance portions 150 k 1-150 k 4 (FIG. 6). And, the pin 155 ispositioned in the opening 150 g 1 or 150 g 2.

The description will be made with respect to the operation ofdisengaging the coupling 150 from the drive shaft 180 in interrelationwith the operation of switching to the next developing cartridge B afterthe image forming operation using the cartridge is completed.

In the state where the rotation for the development shaft 153 hasstopped, the axis L2 is substantially co-axial relative to the axis L1in the coupling 150 (rotational force transmitting angular position).And, the development shaft 153 moves in the dismounting direction X6with the cartridge (B), and the receiving surface 150 f or theprojection 150 d in the upstream with respect to the rotationaldirection of the rotary is brought into contact to the free end portion180 b of the drive shaft 180 or the pin 182 (FIG. 25a ). And, the axisL2 begins to incline toward the upstream with respect to the rotationaldirection X4 (FIG. 25 (b)). This direction of inclination is theopposite from that of the inclination of the coupling 150 at the time ofthe engagement of the coupling 150 with the drive shaft 180, withrespect to the development axis 153. It moves, while the upstream freeend portion 150A2 with respect to the rotational direction X4 is kept incontact with the free end portion 180 b by the rotational operation ofthe rotary C. And, in the axis L2, the upstream free end portion 150 A3inclines to the free end 180 b 3 of the drive shaft (FIG. 25 (c)). And,in this state, the coupling 150 is passed by the drive shaft 180,contacting to the free end 180 b 3 (FIG. 25 (d)).

Thus, the coupling 150 moves from the rotation of for transmittingangular position to the disengagement of angular position, so that apart (upstream free-end portion 150A2) of the coupling 150 positionedupstream of the drive shaft 180 with respect to the rotational directionX4 is permitted to circumvent the drive shaft 180. Therefore, thecartridge B moves in accordance with the rotation of the rotary C to theposition of shown in FIG. 21. In addition, before the completion of theone-full rotation of the rotary C, the coupling 150 (the axis L1)inclines toward downstream with respect to a rotational direction X4 byan unshown means. In other words, the coupling 150 moves from thedisengagement angular position to the pre-engagement angular position.By this, after the rotary C completes its one-full rotation, thecoupling 150 is in the state engageable with the drive shaft 180.

As will be apparent from the foregoing description, the angle of thepre-engagement angular position the coupling 150 relative to the axis L1is larger than the angle of the disengaging angular position. This isbecause it is preferable that the pre-engagement angular position is setbeforehand such that during the engagement operation of the coupling,the distance between the upstream free-end the position 150A1 withrespect to the rotational direction X4 and the free-end 180 b 3 of thedrive shaft is relatively longer (FIG. 22b ). This is done inconsideration of the dimensional tolerance of the parts. On thecontrary, at the time of the coupling disengagement, the axis L2inclines in interrelation with the rotation of the rotary C position.Therefore, the downstream pre-end portion 150A2 of the coupling 150 A3moves along the free end portion 180 b 3 the drive shaft. In otherwords, the downstream free-end position 180A2 with respect to therotational direction X4 and the free end portion 180 b 3 aresubstantially aligned with each other in a direction of the axis L1(FIG. 25 (c)). In addition, when the coupling 150 disengages from thedrive shaft 180, the disengagement is possible irrespective of the phasedifference between the coupling 150 and the pin 182.

As shown in FIG. 22, in the rotational force transmitting angularposition of the coupling 150, the angle relative to the axis L1 of thecoupling 150 is such that in the state where the cartridge (B) ismounted to the predetermined position of the apparatus main assembly (A)(the position opposed to the photosensitive drum), the coupling 150receives the transmission of the rotational force from the drive shaft180, and it rotates.

In addition, the pre-engagement angular position of the coupling 150 isthe angular position immediately before the coupling 150 is brought intoengagement with the drive shaft 180 in the process of mounting operationto the predetermined position in accordance with the rotation of therotary C.In addition, the disengaging angular position of the coupling 150 is theangular position relative to the axis L1 of the coupling 150 at the timeof the disengagement of the cartridge (B) from the drive shaft 180, inthe process of the cartridge B moving from the predetermined position inaccordance with the rotation of the rotary C.In the pre-engagement angular position or the disengaging angularposition, the angles beta2 and beta3 which the axis L2 makes with theaxis L1 are larger than the angle beta1 which the axis L2 makes with theaxis L1 in the rotational force transmitting angular position. As forthe angle theta 1, 0 degree is preferable. However, in this embodiment,if the angle beta1 is less than about 15 degrees, the smoothtransmission of the rotational force is accomplished. This is also oneof the effects of this embodiment. As for the angles beta2 and beta3,the range of about 20-60 degrees is preferable.

As has been described hereinbefore, the coupling is pivotably mounted tothe axis L1. And, the coupling 150 inclines in accordance with therotation of the rotary C without interfering with the drive shaft.

Here, according to the above-described embodiment of the presentinvention, even if the cartridge B (developing roller 110) moves inresponse to the movement of the rotary C in one direction which issubstantially perpendicular to the direction of the axis L3 of the driveshaft 180, the drum coupling member 150 can accomplish the coupling(engagement) and the disengagement relative to the drive shaft 180. Thisis because the drum coupling member 150 according to an embodiment ofthe present invention can take the rotational force transmitting angularposition, the pre-engagement angular position, and the disengagingangular position.

Here, as has been described hereinbefore, the rotational forcetransmitting angular position is the angular position of the drumcoupling member 150 for transmitting the rotational force for rotatingthe developing roller 110 to the developing roller 110.

The pre-engagement angular position is the position inclined from therotational force transmitting angular position, and which is the angularposition of the drum coupling member 150 before the drum coupling member150 engages with the rotational force applying portion.

The disengaging angular position is the position which is inclined awayfrom the pre-engagement angular position from the rotational forcetransmitting angular position and which is the angular position of thedrum coupling member 150 for the drum coupling member 150 to disengagefrom the drive shaft 180.

In the above described description, at the time of the disengagement,the upstream receiving surface 150 f or the upstream projection 150 dcontacts with the free end portion 180 b of the drive shaft 180 ininterrelation with the rotation of the rotary C. By this, it has beendescribed that the axis L2 inclines toward the upstream in therotational direction X4. However, in this embodiment, this is notinevitable. For example, a toggle spring (elastic material) is providedadjacent to the rotary fulcrum of the coupling. And, the structure issuch that at the time of the coupling engagement, the urging forceproduces toward the downstream in the rotational direction X4 relativeto the coupling. At the time of the disengagement of the coupling,corresponding to the rotation of the rotary C, the urging force isproduced toward the upstream in the rotational direction X4 to thecoupling contrarily to the case of the engagement by the function ofthis toggle spring. Therefore, at the time of the couplingdisengagement, the upstream receiving surface 150 f or the projection150 d in the rotational direction X4, and the free end portion 180 b ofthe drive shaft 180 are not contacted to each other, and the couplingdisengages from the drive shaft. In other words, as long as the axis L2of the coupling 150 inclines in response to the rotation of the rotaryC, any means is usable. In addition, by the time immediately before thecoupling 150 engages with the drive shaft 180, the coupling is inclinedso that the driven portion 150 a of the coupling faces toward thedownstream in the rotational direction X4. In other words, the couplingis beforehand placed in the state of the pre-engagement angularposition. For this purpose, any means in Embodiment 2 et seqq is usable.

Here, referring to FIG. 26, the description will be made about reductionof the time which the image formation (development) requires in thepresent embodiment. FIG. 26 is a timing chart showing the rotation ofthe developing roller and so on.

Here, with reference to FIG. 26, reduction in time required for imageformation (development) in this embodiment will be described. FIG. 26 isa timing chart for illustrating rotation of the developing roller andthe like.

In FIG. 26, timings of rotation and stop of the developing roller from astate in which the developing apparatus (cartridge) is in a homeposition until the developing roller receives an image formation startsignal to effect development for first color (yellow image formation)and development for a second color (magenta image formation). Withrespect to subsequent developments for third and fourth colors (cyanimage formation and black image formation), illustration is omitted dueto redundant explanation.

In this embodiment, as described above, the engaging operation betweenthe driving shaft 180 and the coupling 150 is completed during therotation of the rotary C or immediately after the stop of the rotationof the rotary C. During or immediately after the stop of the rotation ofthe rotary C, the engaging operation of the coupling 150 with thedriving shaft 180 is completed. Then, the developing roller 110 isplaced in a rotatable state or is rotated.

That is, in the case where the driving shaft 180 has already beenrotated before the coupling 150 goes into an engaging operation with thedriving shaft 180, the coupling 150 starts rotation simultaneously withthe engagement with the driving shaft 180. Then, the developing roller110 starts rotation. Further, in the case where the driving shaft 180 isstopped, the coupling 150 is stopped without being rotated even when theengagement of the coupling 150 with the driving shaft 180 is completed.When the driving shaft 180 starts rotation, the coupling 150 startsrotation. Then, the developing roller 110 starts rotation.

In either case, according to this embodiment, a main assembly-siderotating force transmitting member (e.g., the main assembly-sidecoupling) is not required to be moved forward and back in the axial linedirection.

In this embodiment, the driving shaft 180 has already been rotatedbefore the coupling 150 goes into the engaging operation with thedriving shaft 180. Accordingly, image formation can be started quickly.Therefore, compared with the case where the driving shaft 180 isstopped, the time required for image formation can be further reduced.

Further, in this embodiment, in the rotating state of the driving shaft180, the coupling 150 can be disconnected from the driving shaft 180.

Accordingly, in this embodiment, the driving shaft 180 may also not berotated or stopped in order that the coupling 150 is engaged with ordisengaged from the driving shaft.

That is, according to the coupling 150 in this embodiment, the coupling150 can be engaged with and disengaged from the driving shaft 180,irrespective of the rotation or stop of the driving shaft 180. This isalso one of the remarkable effects of this embodiment.

Thereafter, steps of rotary (developing roller) contact, yellow imageformation, rotary (developing roller) separation, and developing rollerrotation stop are performed in this order. Simultaneously with the startof rotation of the rotary, a disengaging operation of the coupling ofthe cartridge from the driving shaft of the apparatus main assembly isperformed to prepare for a developing operation for the second color.

That is, in this embodiment, the engaging and disengaging operation ofthe coupling can be performed in interrelation with the rotation of therotary. Accordingly, it is possible to shorten a necessary time intervalbetween the first color development and the second color development.Similarly, time intervals between the second color development and thethird color development, between the third color development and thefourth color development, between the home position and the first colordevelopment, and between the fourth color development and the homeposition can also be reduced. Accordingly, a time required for obtaininga color image on a sheet can be reduced. This is also one of theremarkable effects of this embodiment.

Referring to FIG. 27 and FIG. 28, a modified example of the developmentshaft will be described. FIG. 27 is a perspective view of members aroundthe development shaft. FIG. 28 illustrates a characteristic portion inFIG. 27.

In the foregoing description, the free end of the development shaft is aspherical surface, and the coupling is contacted to the sphericalsurface thereof. However, as shown in FIGS. 27 (a) and 28 (a), the freeend 1153 b of the development shaft 1153 may be planate. An edge portion1153 c of a peripheral surface thereof contacts to the coupling 150 torotate the coupling 150. Even with such a structure, the axis L2 isassuredly pivotable relative to the axis L1. In addition, the processingto the spherical surface is unnecessary. For this reason, the cost canbe reduced.

In the foregoing description, another drive transmission pin is fixed tothe development shaft. However, as shown in FIGS. 27 (b) and 28 (b), itmay be separate member from the elongated development shaft. A firstdevelopment shaft 1253A is a member for supporting a rubber portion ofthe developing roller (unshown). In addition, a second development shaft1253B is provided co-axially with the first development shaft 1253A, andhas integrally a rib for the drive transmissions for engaging with thecoupling 150 1253Bc. In this case, geometrical latitude is enhanced byan integral moldings using injection molding and so on. For this reason,the rib part 1253Bc can be enlarged. Therefore, the area of the drivetransmitting portion 1253Bd can be increased. Even if it is adevelopment shaft made of resin material, it can transmit the torqueassuredly. In the Figure, when the coupling 150 rotates in the directionof X8, the drive transmission surface 150 h of the coupling contacts tothe drive transmitting portion 1253Bd of the second drive shaft. Whenthe contact area is wide at this time, a stress applied on the rib1253Bc is small. Therefore, the liability of the damage of the couplingand so on is mitigable. In addition, the first development shaft may bethe simple metal shaft, and the second development shaft may be anintegrally molded product of the resin material. In this case, the costreduction is accomplished.

As shown in FIGS. 27 (c) and 28 (c), the opposite ends 1355 a 1, 1355 a2 of the rotational force transmitting pin (rotational force receivingportion) 1355 are fixed by press-fitting and so on beforehand into thedrive transmission holes 1350 g 1 or 1350 g 2 of the coupling 1350.Thereafter, the development shaft 1353 which has the free end portion1353 c 1, 1353 c 2 formed into the shape of a slot may be inserted. Atthis time, it is preferable that, the engaging portion 1355 b of the pin1355 relative to the free end portion (unshown) of the development shaft1353 is formed into a spherical shape so that the coupling 1350 ispivotable. By fixing the pin 1355 in this manner beforehand, it is notnecessary to increase the size of the standby hole 1350 g of thecoupling 1350 more than needed. Therefore, the rigidity of the couplingis enhanced.

In addition, in the foregoing description, the inclination of the axisof the coupling follows the development shaft free-end. However, asshown in FIGS. 27 (d), 27 (e), and 28 (d), it may follow the contactsurface 1457 a of the bearing member 1457 co-axially with thedevelopment shaft 1453. In this case, the free end surface 1453 b of thedevelopment shaft 1453 is at the level comparable as the end surface ofthe bearing member. And, the rotational force transmitting pin(rotational force receiving portion) 1453 c projected from the free endsurface 1453 b is inserted into the inside of the opening 1450 g of thecoupling 1450. The rotational force is transmitted by this pin 1453 ccontacting to the rotational force transmitting surface (rotationalforce transmitting portion) 1450 h of the coupling. In this manner, thecontact surface 1457 a at the time of the inclination of the coupling1450 is provided on the supporting member 1457. By this, there is nonecessity of processing the development shaft directly, and themachining cost can be reduced.

In addition, similarly, the spherical surface at the free end may be amolded resin part which is a separate member. In this case, themachining cost of the shaft can be reduced. This is because theconfiguration of the shaft processed by cutting and so on can besimplified. In addition, a range of the spherical surface of the shaftfree-end may be narrowed, and the machining cost may be reduced bylimiting the range which requires highly precise processing.

Referring to FIG. 29, the description will be made about a modifiedexample of the drive shaft. FIG. 29 is a perspective view of drive shaftand development driving gear.

Similarly to the development shaft, it is possible to form the free endof the drive shaft 1180 into a flat surface 1180 b as shown in FIG. 29(a). By this, the configuration of the shaft is simple, and themachining cost can be reduced. A pin (rotational force applying portion)is designated by the reference numeral 1182.

In addition, similarly to the development shaft, the drive transmittingportion 1280 c 1, 1280 c 2 may be integrally molded with the drive shaft1280 as shown in FIG. 29 (b). When the drive shaft is a molded resinpart, the drive transmitting portion can be molded as an integral part.Therefore, the cost reduction can be accomplished.

As shown in FIG. 29 (c), in order to narrow the range of the free endportion 1380 b of the drive shaft 1380, an outer diameter of the shaftfree end 1380 c may be decreased than the outer diameter of a main part1380 a. The free end portion 1380 b requires degree of accuracy, inorder to determine the position of the coupling (unshown) as describedabove. For this reason, the surface which requires high degree ofaccuracy can be reduced by limiting the spherical range only to thecontact portion of the coupling. By this, the machining cost can belowered. In addition, the unnecessary free end of the spherical surfacemay be cut similarly.

In addition, in the foregoing embodiments, in the direction of the axisL1, there is no play between the developing roller and the apparatusmain assembly. Here, the positioning method of the developing rollerwill be described with respect to the direction of the axis L1 as to,when play exists. In other words, the coupling 1550 is provided with atapered surface 1550 e, 1550 h. As for the drive shaft, a force isproduced in a thrust direction by the rotation. By this, the couplingand the developing roller are positioned with respect to the directionof the axis L1. Referring to FIG. 30 and FIG. 31, this will be describedin detail. FIG. 30 is a perspective view and a top plan view of thecoupling alone. FIG. 31 is an exploded perspective view of the driveshaft, the development shaft, and the coupling.

As shown in FIG. 30 (b), the rotational force receiving surface 1550 eforms an angle alpha 5 relative to the axis L2. When the drive shaft 180rotates in the T1 direction, the pin 182 and the receiving surface 1550e contact to each other. Then, a component force is applied in the T2direction to the coupling 1550, and the coupling is moved in the T2direction. In more detail, the coupling 1550 moves until the drivingshaft receiving surface 1550 f (FIG. 31a ) of the coupling 1550 contactsto the free end 180 b of the drive shaft 180. By this, the position withrespect to the direction of the axis L2 of the coupling 1550 isdetermined. In addition, the free end 180 b is a spherical surface, andthe driving shaft receiving surface 1550 f of the coupling 1550 is aconic surface. For this reason, in the direction perpendicular to theaxis L2, the position of the driven portion 1550 a of the coupling 1550relative to the drive shaft 180 is determined.

In addition, as shown in FIG. 30 (c), the rotational force transmittingsurface (rotational force transmitting portion) 1550 h forms the anglealpha 6 relative to the axis L2. When the coupling 1550 rotates in theT1 direction, the transmitting surface 1550 h and the pin 155 contact toeach other. Then, a component force is applied in the T2 direction tothe pin 155, and the pin is moved in the T2 direction. And, thedevelopment shaft 153 moves until the free end 153 b of the developmentshaft 153 contacts to the development bearing surface 1550 i (FIG. 31b )of the coupling 1550. By this, the position of the development shaft 153(developing roller) with respect to the direction of the axis L2 isdetermined.

In addition, the development bearing surface 1550 i of the coupling 1550is a conic surface, and the free end 153 b of the development shaft 153is the spherical surface. For this reason, with respect to the directionperpendicular to the axis L2, the position of the driving portion 1550 bof the coupling 1550 relative to development shaft 153 is determined.

The taper angles alpha 5 and alpha 6 are selected so as to be sufficientfor producing the force for moving the coupling and the developingroller in the thrust direction. And, the angles differ depending on theload. However, if other means for determining the position of the thrustdirection is provided, the taper angles alpha 5 and alpha 6 may besmall.

For this reason, as has been described hereinbefore, the coupling isprovided with the taper for producing the retracting force in thedirection of the axis L2, and with the conic surface for determining theposition in the direction perpendicular to the axis L2. By this, theposition in the direction of the axis L2 of the coupling and theposition in the direction perpendicular to the axis can be determinedsimultaneously. In addition, further assured transmission of therotational force can be accomplished. This will be described. When therotational force receiving surface or the rotational force transmittingsurface of the coupling is not given the taper angle which has beendescribed above, the rotational force transmitting surface or therotational force receiving surface of the coupling inclines due toinfluence and so on of dimensional tolerance, and the component force isproduced in the direction (opposite direction to T2 of FIG. 30) of theaxis L2. By this, the contact between the rotational force receivingsurface and the rotational force transmitting surface of the drivetransmission pin and the coupling is disturbed. However, with the abovedescribed structure, such the problem is avoidable.

However, it is not inevitable that the coupling is provided with bothsuch the retracting taper and the positioning conic surface. Forexample, in place of the taper for pulling in the direction of the axisL2, a part for urging in the direction of the axis L2 may be added. Fromnow on, as long as there is no particular description, the case whereboth the tapered surface and the conic surface are formed will bedescribed.

Referring to FIG. 32, the description will be made about the means forregulating the direction of the inclination of the coupling relative tothe cartridge for the engagement between the coupling, and the driveshaft of the apparatus main assembly. FIG. 32 is a side viewillustrating a major part of the driving side of the cartridge, and FIG.33 is a sectional view taken along S7-S7 of FIG. 32.

Here, in order to regulate the inclining direction of the coupling 150relative to the cartridge B, the supporting member (mounting member)1557 is provided with a regulating portion 1557 h 1 or 1557 h 2. Thisregulating portion 1557 h 1 or 1557 h 2 is provided so that it becomessubstantially parallel to the rotational direction X4 immediately beforethe coupling engages with the drive shaft 180. In addition, theintervals D7 thereof is slightly larger than outer diameter of thedriving portion 150 b of the coupling 150 phi D6. By this, the coupling150 is pivotable in the rotational direction X4. In addition, thecoupling is pivotable in all the directions relative to the developmentshaft. For this reason, irrespective of the phase of the developmentshaft, the coupling can be inclined in the regulated direction.Therefore, it becomes easy to insert the drive shaft (unshown) into theinsertion opening 150 m for the drive shaft of the coupling 150 muchmore assuredly. Therefore, they are more assuredly engageable.

In addition, in the foregoing description, the angle in thepre-engagement angular position of the coupling 150 relative to the axisL1 is larger than the angle of the disengaging angular position (FIG.22, FIG. 25). However, this is not inevitable. Referring to FIG. 34, thedescription will be made.

FIG. 34 is a longitudinal sectional view for illustrating the mountingprocess of the coupling. As shown in FIG. 35, in the state of (a) themounting process of the coupling in the direction of the axis L1, thedownstream free end position 1850A1 with respect to the rotationaldirection X4 is closer to the direction of the driving shaft 182 (therotational force applying portion) than the drive shaft free end 180 b3. In the state of (b), the free end position 1850A1 is contacted to thefree end portion 180 b. At this time, the free end position 1850A1 movestoward the development shaft 153 along the downstream free end portion180 b of the drive shaft 180 with respect to the rotational direction X4of the rotary. And, the free end position 1850A1 passes by the free endportion 180 b 3 of the drive shaft 180 at this position, the coupling150 takes the pre-engagement angular position (FIG. 34 (c)). And,finally the engagement between the coupling 1850 and the drive shaft 180is established ((rotational force transmitting angular position) FIG. 34(d)). When the free end portion 1850A1 passes by the free end 180 b 3,the free end position 1850A1 is contacted to the free end 180 b 3, or ispositioned in the development shaft (153) or developing roller side

An example of this embodiment will be described.

First, as shown in FIG. 5, the shaft diameter of the development shaft153 is ΦZ1, the shaft diameter of the pin 155 is ΦZ2, and the length isZ3. As shown in FIG. 6 (d), (e) and (f), the maximum outer diameter ofthe driven portion 150 a of the coupling 150 is ΦZ4 the diameter of aphantom circle C1 (FIG. 6(d)) which forms the inner ends of theprojections 150 d 1 or 150 d 2 or 150 d 3, 150 d 4 is ΦZ5, and themaximum outer diameter of the driving portion 150 b is ΦZ6. Referring toFIGS. 22 and 25, the angle formed between the coupling 150 and the conicdrive shaft receiving surface 150 f is α2, and the angle formed betweenthe coupling 150 and the shaft receiving surface 150 i is α1. A shaftdiameter of the drive shaft 180 is ΦZ7, the shaft diameter of the pin182 is ΦZ8, and the length is Z9). In addition, the angle relative tothe axis L1 in the rotational force transmitting angular position is βi,the angle in the pre-engagement angular position is β2, and the angle inthe disengaging angular position is β3. In this example,

Z1=8 mm; Z2=2 mm; Z3=12 mm; Z4=15 mm; Z5=10 mm; Z6=19 mm; Z7=8 mm; Z8=2mm; Z9=14 mm; α1=70 degrees; α2=120 degrees; β1=0 degree; β2=35 degrees;β3=30 degrees.

It has been confirmed with these settings, the devices of thisembodiment works satisfactorily. However, these settings do not limitthe present invention.

Embodiment 2

Referring to FIG. 36-FIG. 38, the second embodiment to which applied thepresent invention will be described.

In this embodiment, a means for inclining the axis of the couplingrelative to the axis of the developing roller.

In the description of this embodiment, the same reference numerals as inEmbodiment 1 are assigned to the elements having the correspondingfunctions in this embodiment, and the detailed description thereof isomitted for simplicity. This applies also about the other embodimentdescribed in the below.

FIG. 36 is a perspective view which illustrates a coupling lockingmember (this is peculiar to the present embodiment) pasted on thesupporting member. FIG. 37 is an enlarged perspective view of a majorpart of the driving side of the cartridge. FIG. 38 is a perspective viewand a longitudinal sectional view which illustrate an engaged statebetween the drive shaft and the coupling.

As shown in FIG. 36, the supporting member 3157 has a space 3157 b whichsurrounds a part of coupling. A coupling locking member 3159 as amaintaining member for maintaining the inclination of the coupling 3150is pasted on a cylinder surface 3157 i which constitutes the spacethereof. As will be described hereinafter, this locking member 3159 is amember for maintaining temporarily the state where the axis L2 inclinesrelative to the axis L1. In other words, as shown in FIG. 36, the flangeportion 3150 j of the coupling 3150 contacts to this locking member3159. By this, the axis L2 maintains the state of inclining toward thedownstream with respect to the rotational direction (X4) of thecartridge relative to the axis L1. Therefore, as shown in FIG. 46, thelocking member 3159 is disposed on the upstream cylinder surface 3157 iof the bearing member 3157 with respect to the rotational direction X4.As the material of the locking member 3159, the material which has arelatively high coefficient of friction, such as the rubber and theelastomer, or the elastic materials, such as the sponge and the flatspring, are suitable. This is because, the inclination of the axis L2can be maintained by the frictional force, the elastic force, and so on.

Referring to FIG. 38, the engaging operation (a part of mounting anddismounting operation of the cartridge) for engaging the coupling 3150with the drive shaft 180 will be described. FIGS. 38 (a 1) and (b 1)illustrate the state immediately before the engagement, and FIGS. 38 (a2) and (b 2) illustrate the state of the completion of the engagement.

As shown in FIG. 38 (a 1) and FIG. 38 (b 1), the axis L2 of the coupling3150 inclines toward the downstream (retracted position) with respect tothe rotational direction X4 relative to the axis L1 beforehand by theforce of the locking member 3159 (pre-engagement angular position). Bythis inclination of the coupling 3150, by, in the direction of the axisL1, the downstream (with respect to the mounting direction) free endportion 3150A1 is closer to the cartridge (developing roller) side thanthe drive shaft free end 180 b 3. And, the upstream (with respect to themounting direction) free end portion 3150A2 is closer to the pin 182than the free end 180 b 3 of the drive shaft 180. In addition, at thistime, as has been described in the foregoing, the flange portion 3150 jof the coupling 150 is contacted to the locking member 3159. And, theinclined state of the axis L2 is maintained by the frictional forcethereof.

Thereafter, the cartridge B moves to the rotational direction X4. Bythis, the free end surface 180 b or the free end of the pin 182 contactsto the driving shaft receiving surface 3150 f of the coupling 3150. And,the axis L2 approaches to the direction in parallel with the axis L1 bythe contact force (force revolving the rotary) thereof. At this time,the flange portion 3150 j is departed from the locking member 3159, andbecomes into the non-contact state.

And, finally, the axis L1 and the axis L2 are substantially co-axialwith each other.

And, the coupling 3150 is in the waiting (stand-by) state fortransmitting the rotational force (FIG. 38 (a 2), (b 2)) (rotationalforce transmitting angular position).

Similarly to embodiment 1, the rotary C swings about a swing center axisand contacts the developing roller 110 to the photosensitive drum 107.And, the rotational force of the motor 64 is transmitted to the coupling3150, the pin 155, the development shaft 153, and the developing roller110 through the drive shaft 180. The axis L2 is substantially co-axialwith the axis L1 during the rotation. For this reason, the lockingmember 3159 is not contacted with the coupling 3150 and does notinfluence on the drive of the coupling 3150.

After the image formation finishes, the rotary C swings in the oppositedirection and the developing roller 110 spaces from the photosensitivedrum 107. And then, in order to carry out the image formation for thenext color, the rotary C begins the revolution. In that case, thecoupling 3150 disengages from the drive shaft 180. In other words, thecoupling 3150 is moved to the disengaging angular position from therotational force transmitting angular position. Since the operation inthat case is the same as that of Embodiment 1 (FIG. 25), the descriptionis omitted for simplicity.

In addition, by the time the rotary C carries out one full revolution,the axis L2 of the coupling 3150 inclines toward the downstream in therotational direction X4 by unshown means. In other words, the coupling3150 is moved from the disengaging angular position to thepre-engagement angular position by way of the rotational forcetransmitting angular position. By doing so, the flange portion 3150 jcontacts to the locking member 3159, and the inclined state of thecoupling is maintained again.

As has been described hereinbefore, the inclined state of the axis L2 ismaintained by the locking member 3159 pasted on the supporting member3157. By this, the engagement between the coupling and the drive shaftis established much more assuredly.

In the present embodiment, the locking member 3159 is pasted at theupstreammost side of the inner surface 3157 i of the supporting memberwith respect to the rotational direction X4. However, this is notinevitable. For example, what is necessary is the position where theinclined state thereof can be maintained when the axis L2 is inclined.

The locking member 3159 has been described as contacting with the flangeportion (FIG. 38b 1) 3150 j (FIG. 38b 1). However, the contact positionmay be the driven portion 3150 a (FIG. 38b 1).

In this embodiment, although it has been described that the lockingmember is a separate member, this is not inevitable. For example, it maybe molded integrally with the supporting member 3157 (2 color molding,for example), and the supporting member 3157 may be directly contactedto the coupling 3150 in place of the locking member 3159. Or, thesurface of the coupling may be roughened for the increase of thecoefficient of friction.

In addition, although it has been described that the locking member 3159is pasted on the development supporting member 3157, it may be anythingif it is a member fixed on the cartridge B.

Embodiment 3

Referring to FIG. 39-FIG. 42, a third embodiment of the presentinvention will be described.

The description will be made as to means for inclining the axis L2relative to the axis L1.

As shown in FIG. 39 (perspective view), a coupling pressing memberpeculiar to the present embodiment is mounted to the supporting member.FIG. 40 is a perspective view illustrating the coupling pressing member.FIG. 41 is an enlarged perspective view of the major part of the drivingside of the cartridge. FIG. 42 is a perspective view illustrating theengaging operation and a longitudinal sectional view of the coupling.

As shown in FIG. 39, spring supporting portions 4157 e 1, 4157 e 2 areprovided on the inner surface 4157 i of the supporting member (mountingmember) 4157. In addition, the coil parts 4159 b, 4159 c of torsion coilsprings (coupling urging members) 4159 are mounted to the supportingportions 4157 e 1, 4157 e 2. And, as shown in FIG. 40, a contact portion4159 a of the urging member 4159 contacts to the driven portion 4150 aside of a flange portion 4150 j of the coupling 4150. The spring 4159 istwisted to produce an elastic force. By this, the axis L2 of thecoupling 4150 is inclined relative to the axis L1 (FIG. 41,pre-engagement angular position). The contact position of the urgingmember 4159 to the flange portion 4150 j is set downstream of the centerof the development shaft 153 with respect to the rotational directionX4. For this reason, the axis (L2) is inclined relative to the axis (L1)so that the driven portion 4150 a side is directed to the downstreamwith respect to the rotational direction (X4).

In the present embodiment, although the torsion coil spring is used asthe urging member (elastic material), this is not inevitable. The anymeans which can produce the elastic forces, such as for example, leafsprings, rubber, and sponge, is usable. However, in order to incline theaxis L2, a certain amount of stroke is required. Therefore, a memberwhich can provide the stroke is desirable.

In addition, the spring supporting portions 4157 e 1, 4157 e 2 of thesupporting member 4157 and the coil parts 4159 b, 4159 c function as theretention rib for the coupling described with respect to Embodiment 1(FIG. 9, FIG. 12).

Referring to FIG. 42, the engaging operation (a part of rotatingoperation of the rotary) between the coupling 4150 and the drive shaft180 will be described. (a1) and (b1) in FIG. 42 are views immediatelybefore the engagement, and (a2) and (b2) in FIG. 42 illustrate the statewhere the engagement has completed. (a3) and (b3) in FIG. 42 are viewsin the state where the engagement has been released, and (a4) and (b4)in FIG. 42 are views in the state where the axis L2 inclines toward thedownstream with respect to the rotational direction X4 again.

In the state (retreating position of the coupling 4150) of FIGS. 42 (a1) and 42 (b 1), the axis L2 thereof is beforehand inclined toward thedownstream with respect to the rotational direction X4 relative to theaxis L1 (pre-engagement angular position). Thus, the coupling 4150 isinclined. By this, in the direction of the axis L1, the downstream freeend position 4150A1 with respect to the rotational direction X4 ispositioned in the cartridge (developing roller) side beyond the driveshaft free-end 180 b 3. In addition, the upstream free end position4150A2 with respect to the rotational direction X4 is positioned beyondthe pin 182 side from the drive shaft free-end 180 b 3. In other words,as has been described hereinbefore, the flange portion 4150 j is pressedby the urging member 4159. For this reason, the axis L2 is inclinedrelative to the axis L1 by the urging force.

Thereafter, the cartridge B moves in the rotational direction X4. Bythis, the free end surface 180 b or the free end of the pin 182 contactsto the driving shaft receiving surface 4150 f of the coupling 4150. And,the axis L2 approaches to the angle in parallel with the axis L1 by thecontact force (force of rotating the rotary).

Simultaneously, the flange portion 4150 j and the urging spring 4159contact with each other. By this, the spring 4159 is twisted to increasethe moment. Finally, the axis L1 and the axis L2 become substantiallyco-axial with each other, and the coupling 4150 is in the rotationlatency state (FIG. 42 (a 2), (b 2)). (rotational force transmittingangular position).

Similarly to embodiment 1, the rotational force is transmitted to thecoupling 4150, the pin 155, the development shaft 153, and thedeveloping roller 110 through the drive shaft 180 from the motor 64. Theurging force of the urging member 4159 applies to the coupling 4150 atthe time of the rotation. However, if the driving torque of the motor 64has a sufficient margin, the coupling 4150 will rotate with highprecision.

When the rotary further revolves, the coupling 4150 will separate fromthe drive shaft 180 as shown in FIGS. 42 (a 3) and (b 3). In otherwords, the free end spherical surface 180 b of the drive shaft 180pushes the driving shaft receiving surface 4150 f of the coupling. Bythis, the axis L2 inclines toward the opposite direction (oppositedirection from the rotational direction X4) with respect to the axis L1(disengaging angular position). By doing so, the urging member 4159 isfurther twisted so that the urging force (elastic force) furtherincreases. For this reason, after the coupling 4150 disengages from thedrive shaft 180, the axis L2 is again inclined in the rotationaldirection X4 relative to the axis L1 by the urging force of the urgingmember 4159 (pre-engagement angular position, FIG. 42 (a 4), (b 4)). Bythis, even if the means for inclining the axis L2 toward thepre-engagement angular position by the time the drive shaft 180 and thecoupling 4150 are again coupled by the revolution of the rotary C witheach other is not provided particularly, the drive shaft 180 and thecoupling 4150 are connectable (engageable) with each other.

As has been described hereinbefore, the urging is effected by the urgingmember 4159 provided on the supporting member 4157. By this, the axis L2is inclined relative to the axis L1. Therefore, the inclined state ofthe coupling 4150 is maintained assuredly and the engagement (coupling)between the coupling 4150 and the drive shaft 180 is ensured.

The position of the urging member in the present embodiment is notrestrictive. For example, it may be another position on the supportingmember 4157, or may be a member other than such a member.

In addition, the urging direction of the urging member 4159 is the sameas the direction of the axis L1, but if the axis L2 inclines in thepredetermined direction, it may be any direction.

In addition, the energizing position of the urging member 4159 is theposition of the flange portion 4150 j, but if the axis L2 inclinestoward the predetermined direction, it may be any position of thecoupling.

Embodiment 4

Referring to FIG. 43-FIG. 46, the fourth embodiment of the presentinvention will be described.

The means for inclining the axis L2 with respect to the axis L1 will bedescribed.

FIG. 43 is an exploded perspective view illustrating the state beforethe assembly of the major members of the developing cartridge. FIG. 44is an enlarged side view of the driving side of the cartridge. FIG. 45is a longitudinal sectional view which schematically illustrates thestructure for the axis L2 to incline. FIG. 46 is the drive shaft and alongitudinal sectional view illustrating the engaging operation betweenthe coupling.

As shown in FIG. 43 and FIG. 45, a coupling locking member 5157 k isprovided on the supporting member (mounting member) 5157. When thesupporting member 5157 is assembled in the direction of the axis L1,while a part of a locking surface 5157 k 1 of an of the locking member5157 k contacts with the inclined surface 5150 m of the coupling 5150,the part engages with the upper surface 5150 j 1 of a flange portion5150 j. At this time, the flange portion 5150 j is mounted with play(angle alpha 49) between locking surface 5157 k 1 and circular columnportion of the development shaft 153 153 a. Even when the dimensionaltolerances of the coupling 5150, the bearing member 5157, and thedevelopment shaft 153 vary, the flange portion 5150 j 1 can lockassuredly to the locking portion 5157 k 1 of the bearing member 5157 byproviding this play (angle alpha 49).

And, as shown in FIG. 45 (a), the axis L2 is inclined so that the drivenportion 5150 a side faces the downstream with respect to the rotationaldirection X4 relative to the axis L1. In addition, since the flangeportion 5150 j extends over the full-circumference, it can be mountedregardless of the phase of the coupling 5150. Furthermore, as has beendescribed with respect to Embodiment 1, the coupling is pivotable in therotational direction X4 by the regulating portion 5157 h 1 or 5157 h 2.In addition, in this embodiment, the locking member 5157 k is providedat the downstreammost position in the rotational direction X4.

As will be described hereinafter, as shown in FIG. 45 (b), in the stateof being in engagement with the drive shaft 180, the flange portion 5150j is released from the locking member 5157 k. In addition, the coupling5150 is free from the locking portion 5157 k. In assembling thesupporting member 5157, when the coupling 5150 is not able to beretained in the inclined state, the driving portion 5150 b of thecoupling is pushed by tool and so on (the direction of an arrow X14 ofFIG. 45 (b)). By this, the coupling 5150 will mount easily (FIG. 45(a)).

Referring to FIG. 46, the engaging operation (a part of rotary rotatingoperation) between the coupling 5150 and the drive shaft 180 will bedescribed. FIG. 46 (a) shows a view immediately before the engagement,and (b) is a view after a part of coupling 5150 passes the drive shaft180. In addition, (c) illustrates the state where the inclination of thecoupling 5150 is released by the drive shaft 180, and (d) illustratesthe engaged state.

In the state of FIGS. 46 (a) and (b), the coupling 5150 takes aretreating position, where the axis L2 thereof is inclined beforehand tothe rotational direction X4 relative to the axis L1 (pre-engagementangular position). The downstream free end position 5150A1 with respectto the rotational direction X4 takes a position closer to the cartridgeB (developing roller) than the drive shaft free-end 180 b 3 by theinclination of the coupling 5150. In addition, the upstream free endposition 5150A2 with respect to the rotational direction X4 ispositioned in the pin 182 side from the drive shaft free-end 180 b 3. Atthis time, as has been described hereinbefore, the flange portion 5150 jis contacted to the locking surface 5157 k 1 of the locking portion 5157k, and, as for the coupling, the inclined state is maintained.

Thereafter, as shown in (c), the cartridge B moves in the rotationaldirection X4. By this, tapered driving shaft receiving surface 5150 f ofthe coupling 5150 or driven projection 5150 d contacts to the free endportion 180 b of the drive shaft 180, or the pin 182. The flange portion5150 j separates from the locking surface 5157 k 1 by the force by thecontact. By this, the lock relative to the supporting member 5157 of thecoupling 5150 is released. And, in response to the rotation of therotary C, the coupling is inclined so that the axis L2 becomes parallelto the axis L1. After the passage of the flange portion 5150 j, thelocking member 5157 k returns to the previous position by the restoringforce. Then, the coupling 5150 becomes free from the locking portion5157 k. And, finally, as shown in (d), the axis L1 and the axis L2become substantially co-axial, and the rotation latency state isestablished (rotational force transmitting angular position).

And, after the image forming operation finishes, the next cartridge Breaches the developing position. For this purpose, the rotary C rotatesagain. In that case, the coupling 5150 disengages from the drive shaft180. In other words, the coupling 5150 is moved to the disengagingangular position from the rotational force transmitting angularposition. Since the detail of the operation in that case is the same asEmbodiment 1 (FIG. 25), the description is omitted for simplicity.

In addition, by the time the rotary C carries out one-full revolution,the axis L2 of the coupling 5150 inclines to the downstream with respectto the rotational direction X4 by an unshown means. In other words, thecoupling 5150 is moved from the disengaging angular position to thepre-engagement angular position by way of the rotational forcetransmitting angular position. By doing so, the flange portion 5150 jcontacts to the locking member 3157 k, and the inclined state of thecoupling is maintained again.

As has been described hereinbefore, the inclining direction of thecoupling 5150 is regulated by the locking portion 5157 k of thesupporting member 5157. By this, the inclined state of the coupling 5150is maintained even more assuredly. And, the engagement between thecoupling 5150 and the drive shaft 180 is established assuredly.Furthermore, at the time of the rotation, the structure that the lockingportion 5157 k does not contact to the coupling 5150 also contributes tothe stabilized transmission of the rotational force.

In this embodiment, the locking portion 5157 k has an elastic portion.However, the locking portion 5157 k may not have the elastic portion andit may be formed in the shape of a rib by which the flange portion ofthe coupling is made to deform. By this, the similar effects areprovided.

In addition, the locking portion 5157 k is provided at thedownstreammost side with respect to the rotational direction X4.However, the locking portion 5157 k may be any position if the axis L2can maintain the state of inclining to the predetermined direction.

In this embodiment, the locking portion 5157 k is constituted by a partof supporting members. However, the locking portion 5157 k may beprovided in another position of the supporting member, or it may be amember other than the supporting member. In addition, the lockingportion may be a separate member.

In addition, the present embodiment, and Embodiment 2 or Embodiment 3may be implemented simultaneously, and the engagement and thedisengaging operations of the coupling relative to the drive shaft arecarried out even more assuredly in this case.

Embodiment 5

Referring to FIG. 47-FIG. 51, the fifth embodiment of the presentinvention will be described.

The means for inclining the axis L2 relative to the axis L1 will bedescribed.

FIG. 47 shows a view of supporting member and rotary flange of thedriving side, as seen in the direction of the axis L1. FIG. 48 shows aview of the members of the apparatus main assembly, as seen in thedirection of the axis L1. FIG. 49 is the same as FIG. 48, however thelocus of the coupling is added. FIG. 50 is a sectional view taken alonglines S10-S10, S11-S11, S12-S12, S13-S13, S14-S14 in FIG. 49.

First, referring to FIG. 47, the structure for regulating the incliningdirection of the coupling 150 will be described. The supporting member7157 rotates integrally with the rotary C. The member 7157 is providedwith regulating portions 7157 h 1 or 7157 h 2 for permitting theinclination, only in said one direction, of the coupling 7150. Adistance D6 between these regulating portions is slightly larger thanthe outer diameter (unshown) of the driving portion 7150 b of thecoupling 7150 to permit the rotation of the coupling 7150. Theregulating portions 7157 h 1 and 7157 h 2 are inclined by angle of alpha7 relative to the rotational direction X4. By this, the coupling 7150 ispivotable to the alpha7 X5 direction with respect to the rotationaldirection X4.

Referring to FIG. 48, the method for inclining the coupling 7150 will bedescribed. In the present embodiment, a regulation rib 1630R fixed tothe driving side 180 is provided. The radius of the surface inside theradial direction of the rib 1630R is gradually reduced toward thedownstream portion 1630Rb from the upstream part 1630Ra, R-2 withrespect to the rotational direction X4. And, the radius R-1 of thissurface is selected so that it contacts and is interfered by the outerperiphery 7150 c 1 of the intermediate part 7150 c of the coupling FIG.45.

When the coupling 7150 contacts with the regulation rib 1630R, thecoupling 7150 is pushed toward the rotation axis of the rotary C. Atthis time, the coupling 7150 is regulated by the regulating portions1557 h 1 or 1557 h 2 in the movement direction. For this reason, thecoupling 7150 is inclined to the X5 direction.

An increase of the degree of the interference will also increase theinclination of the coupling 7150. The configuration of the regulationrib 1630R is such that before the coupling 7150 engages with the driveshaft 180, the amount of interferences is increased until theinclination angle of the coupling 7150 becomes the engageable angle. Inthe present embodiment, the section from the position 1630Rb to theposition 1630Rc is located on the same radius positions from therotation axis of the rotary C. The radius is indicated by R-1.

FIG. 49 illustrates the locus until the coupling 7150 engages with thedrive shaft 180 along the guide 1630R with the rotation of the rotary C.A section taken along lines S10-S10-S14-S14 in FIG. 49 is shown in FIG.50(a)-(e).

The coupling 7150 enters the region of the regulation rib 1630R in thedirection of X4. At this time, the coupling is faced in the direction ofX6 which is the substantially advancing direction, is faced in thereverse direction of X7, or is faced in the inbetween direction thereof.Here, the case where the coupling 7150 faces the direction of X7 will bedescribed.

The inclining direction X5 (FIG. 47) of the coupling 7150 is angle alpha7 relative to the rotational direction X4. In view of this, when thecoupling 7150 inclines toward the X7 direction, the driven portion 7150a of the coupling outwardly inclines with respect to the radialdirection of the rotary C (FIG. 47). The gap G1 is provided between thecoupling 7150 and the regulation rib 1630R in the place where it entersthe range of the regulation member 1630R.

When the rotation of the rotary C advances to the S11-S11 section, thecoupling 7150 and the regulation rib 1630R contact to each other (FIG.50b ). The radius of the regulation rib 1630R is reduced gradually.Therefore, a degree of the interference increases with the advancementof the coupling 7150.

In the position of the section S12-S12, the regulation rib 1630R pushesup the coupling 7150, and it is co-axial with the development shaft(FIG. 50c ). At this time, the motion of the coupling 7150 is regulatedby the regulation rib 1630R. In view of this, the coupling 7150 ispivotable only in the X8 direction (only in X6 direction in thecross-sectional position of S10-S10), and cannot be inclined toward theopposite direction X8 thereto.

In the cross-sectional S13-S13 position, the degree of the interferenceof the coupling relative to the regulation rib 1630R increases. In viewof this, the coupling 7150 is pushed up by the rib 1630R, and isforcedly inclined in the direction of X9 (X8 direction in the sectionS12-S12) (FIG. 50 (d)). (pre-engagement angular position).

In this state, the rotary C is rotated until the coupling becomesco-axial with the drive shaft 180 (S14-S14 section position). By this,the coupling 7150 can be engaged with the drive shaft 180 through theoperation similar to Embodiment 1 (rotational force transmitting angularposition).

Thereafter, after the image formation finishes, the coupling 7150 isdisengaged from the drive shaft 180, so that, it is a series ofoperations are finished (since the disengaging operation is the same asthose of the foregoing embodiments, the description is omitted forsimplicity). This operation is repeated for every image formation.

In order for the coupling to interfere with the regulation rib, thecoupling is contacted to it from the outside with respect to the radialdirection, and inclines the coupling thereby. However, it is regulatedsuch that the angle alpha 7 (in FIG. 47 the X5 direction) of theregulating portions 1557 h 1 or 1557 h 2 are line-symmetrical withrespect the tangential direction (the X4 direction). By this, the sameoperation is carried out when the regulation rib 1630R is contacted fromthe radial inside.

The cartridge does not need to be provided with the mechanism forinclining the coupling by the orientation of the coupling 7150 beingregulated by the regulation rib 1630R. By this, the cost reduction ofthe cartridge can be accomplished.

In this embodiment, the coupling may be assuredly slid along the rib byapplying the force to the coupling with the spring and so on.

In addition, it is moved on the guide rib through an intermediate part7150 c of the coupling. However, if the inclination of the coupling ispossible, it may move on the guide rib through the position other thanthe intermediate part.

In addition, the present embodiment, Embodiment 2 or Embodiment 3, orEmbodiment 4 may be implemented simultaneously, and in such a case,Engagement and disengagement operations of the coupling can be ensured.

Embodiment 6

Referring to FIG. 51-FIG. 52, the sixth embodiment of the presentinvention will be described.

In this embodiment, the configuration of another coupling is employed.

FIG. 51 is an illustration of the coupling which is the mainconstituent-elements of the present embodiment. FIG. 52 is alongitudinal sectional view illustrating engaged state and state beforethe engagement between drive shaft of the apparatus main assembly andthe coupling.

First, referring to FIG. 51, the configuration of the coupling per sewill be described. FIG. 51 (a) shows a view of the coupling, as seenfrom the apparatus main assembly side, FIG. 51 (b) shows a view of thecoupling, as seen from the developing roller side, and FIG. 51 (c) is asectional view taken along S4-S4 in FIG. 51 (a).

The coupling 8150 is generally cylindrical. As shown in FIG. 51 (c) thecoupling 8150 has a drive shaft insertion opening portion 8150 m and adevelopment shaft insertion opening portion 8150 p for receiving therotational force from the drive shaft of the apparatus main assembly.The opening 8150 m is provided with a tapered driving shaft receivingsurface 8150 f. On the cylindrical inner surface, a plurality of drivenprojections 8150 d (8150 d 1 or 8150 d 2 or 8150 d 3, 8150 d 4) in theform of ribs are disposed. In addition, in FIG. 51 (a), a rotationalforce transmitting surface (rotational force receiving portion) 8150 e1-e 4 is provided downstream of the projection 8150 d with respect tothe clockwise direction. And, the rotational force (driving force) istransmitted by the contact of the pin 182 of the drive shaft 180 to thetransmitting surface 8150 e 1-e 4 to the coupling 8150.

The opening 8150 p is provided with a tapered development bearingsurface 8150 i similarly. In addition, the cylindrical inner surface isprovided with the rib-like projections 8150 g 1 or 8150 g 2. Inaddition, in FIG. 50 (b) a transmitting surface (rotational forcetransmitting portion) 8150 h 1 or 8150 h 2 is provided in an upstreamposition of the development drive standby opening 8150 g 1 or 8150 g 2with respect to clockwise direction.

Referring to FIG. 52, the description will be made about the engagingoperation of the coupling.

FIG. 52 (a) is a sectional view illustrating a state before engagingwith the drive shaft 180 after the movements of the development shaft180 and the coupling 8150 in the rotational direction X4. The axis L2inclines to the angle alpha 7 so that a downstream free end position8150A1 with respect to the rotational direction X4 can pass the free endportion 180 b. At this time, The upstream 182 a and the downstream 182 bof the pin 182 maintain the engaged state with the transmitting surface(rotational force receiving portion) 8150 h 1 or 8150 h 2 (FIG. 51c ) ofthe coupling 8150.

FIG. 52 (b) illustrates the coupling 150 having been described withrespect to Embodiment 1, in the orientation the same as FIG. 52 (a). Aswill be understood from FIG. 52 (b), the axis L2 of the coupling 150 isinclined by the angle alpha 7 similarly to FIG. 52 (a). By this, theengagement between upstream pin 155 and the upstream drive transmissionsurface 8150 h 1 is not established with respect to rotational directionX4. In other words, there is a gap of G7 between the pin 155 and thetransmitting surface 150 h 1. On the other hand, in the presentembodiment, the coupling 8150 has the contact portions for therotational force transmission at the two places as shown in FIG. 52 (a).For this reason, the orientation of the coupling is further stabilized.

As has been described hereinbefore, the coupling has a cylindricalshape. By this, even if it is necessary to increase the inclinationangle (pre-engagement angular position) of the coupling, the contactportions for the rotational force transmission in the two places areassured. Therefore, the inclination operation of the stabilized couplingcan be accomplished.

Since the co-axial rotational force transmission between the drive shaft180 and the development shaft 153 and the engagement releasing operationbetween them are the same as that of Embodiment 1, those descriptionsare omitted for simplicity.

Embodiment 7

Referring to FIG. 53, the seventh embodiment of the present inventionwill be described.

The present embodiment is different from Embodiment 1 in theconfiguration of the coupling. FIG. 53(a) is a perspective view of acoupling which has a generally cylindrical shape, and FIG. 53 (b) is asectional view when the coupling mounted to the cartridge engages with adrive shaft.

In FIGS. 53(a) and 53(b), the rotational force is inputted from the mainassembly at the righthand side, and the developing roller at thelefthand is driven.

An input side edge of the coupling 9150 is provided with a plurality ofdriven projections (rotational force receiving portions) 9150 d. In thisembodiment, they are provided at two positions. Entering portions orentrances 9150 k is provided between the drive receiving projections9150 d. The projection 9150 d is provided with a rotational forcereceiving surface (rotational force receiving portion) 9150 e. Arotational force transmitting pin (rotational force applying portion)9182 of the drive shaft 9180 as will be described hereinafter contactsto the rotational force receiving surface 9150 e. By this, a rotationalforce is transmitted to the coupling 9150.

In order to stabilize the torque transmitted to the coupling, aplurality of rotational force receiving surfaces 150 e are desirablydisposed on the same circumference (on a common circle). By thedisposition in this manner, the rotational force transmission radius isconstant and the torque transmitted is stabilized. A sudden increase ofthe torque can be avoided. In addition, from the viewpoint of thestabilization of the drive transmission, the receiving surfaces 9150 eare desirably provided on the opposed positions (180 degrees)diametrically. In addition, the number of the receiving surfaces 9150 emay be any if the pin 9182 of the drive shaft 9180 can be received bythe standing-by portion 9150 k. In the present embodiment, the number istwo. The rotational force receiving surfaces 9150 e may not be on thesame circumference, or they may not be disposed diametrically opposedpositions.

In addition, the cylinder surface of the coupling 9150 is provided withthe standby opening 9150 g. In addition, an opening 9150 g is providedwith the rotational force transmission surface (rotational forcetransmitting portion) 9150 h. The drive transmission pin (rotationalforce receiving member) 9155 (FIG. 53 (b)) of the development shaft 9153contacts to this rotational force transmission surface 9150 h. By this,the rotational force is transmitted to the developing roller 110 fromthe main assembly A.

Similarly to the projection 9150 d, the rotational force transmissionsurface 9150 h is desirably disposed diametrically opposed on the samecircumference.

The configurations of the development shaft 9153 and the drive shaft9180 will be described (FIG. 53(b)). In Embodiment 1, the cylindricalend is a spherical surface. In this embodiment, however, a diameter of aspherical free end portion 9153 b of the end portion is larger than adiameter of a main part 9153 a. With this configuration, the left endportion of the coupling 9150 can incline without interference with themajor part 9150 a. The configuration of the drive shaft 9180 is the sameas that of the development shaft 9150 substantially. In other words, theconfiguration of the free end portion 9180 b is the spherical surface,and the diameter thereof is larger than the diameter of the main part9180 a of the cylindrical shape portion. In addition, the pin(rotational force applying portion) 9182 which pierces through thesubstantial center of the free end portion 9180 b which is the sphericalsurface is provided. The pin 9182 transmits the rotational force to thetransmitting surface or rotational force receiving surface 9150 e of thecoupling 9150.

The development shaft 9150 and the spherical surface of the drive shaft9180 are in engagement with the inner surface 9150 p of the coupling9150. By this, the relative position between the development shaft 9150and the coupling 9150 of the drive shaft 9180 is determined. Theoperation with respect to the mounting and demounting of the coupling9150 relative to the drive shaft 9180 is the same as Embodiment 1, andtherefore, the description thereof is omitted for simplicity.

As has been described hereinbefore, the coupling has the cylindricalshape, and therefore, the position with respect to the directionperpendicular to the direction of the axis L2 of the coupling 9150 canbe determined if the coupling is engaged with the shaft.

A modified example of the coupling will be described further. In theconfiguration of the coupling 9250 shown in FIG. 53 (c), a cylindricalshape and a conical shape are put together. FIG. 53 (d) is a sectionalview of the coupling of this modified example. A driven portion 9250 aof the coupling 9250 (righthand side in the Figure) has a cylindricalshape, and an inner surface 9250 p thereof engages with the sphericalsurface of the drive shaft 9180. Furthermore, it has the abutmentsurface 9250 q and can effect the positioning with respect to the axialdirection between the coupling 9250 and the drive shaft 180. The drivingportion 9250 b has a conical shape (lefthand side of the Figure), and,similarly to Embodiment 1, the position relative to the developmentshaft 153 is determined by the development shaft receiving surface 9250i.

The configuration of the coupling 9350 shown in FIG. 53 (e) is acombination of a cylindrical shape and a conical shape. FIG. 53 (f) is asectional view of this modified example. The driven portion 9350 a ofthe coupling 9350 has a cylindrical shape (righthand side), and theinner surface 9350 p thereof engages with the spherical surface of thedrive shaft 9180. The positioning in the axial direction of the driveshaft 9180 is effected by abutting the spherical surface 9180 c of thedrive shaft 9180 to the edge portion 9350 q formed between thecylindrical portions having different diameters.

The configuration of the coupling 9450 shown in FIG. 53 (g) is acombination of a spherical surface, a cylindrical shape, and a conicalshape. FIG. 53 (h) is a sectional view of this modified example, whereina driven portion 9450 a of the coupling 9450 (righthand side) has acylindrical shape, and the inner surface 9450 p thereof engages with thespherical surface 9450 q of the drive shaft. A spherical surface of thedrive shaft 180 is contacted to a spherical surface 9450 q which is apart of the spherical surface. By this, the position can be determinedwith respect to the direction of the axis L2. Designated by 9250 d, 9350d, 9450 d are projections. Designated by 9250 e, 9350 e and 9450 e arerotational force receiving surfaces (rotational force receivingportion).

Embodiment 8

Referring to FIG. 54-FIG. 56, the eighth embodiment of the presentinvention will be described.

The present embodiment is different from Embodiment 1 in the mountingoperation relative to the drive shaft of the coupling, and the structurewith respect to it. FIG. 54 is a perspective view which illustrates aconfiguration of a coupling 10150 of the present embodiment. Theconfiguration of the coupling 10150 is a combination of the cylindricalshape and conical shape which have been described in Embodiment 7. Inaddition, a tapered surface 10150 r is provided on the free end side ofa coupling 10150. In addition, the surface of an opposite side of thedrive receiving projection 10150 d with respect to the direction of theaxis L1 is provided with an urging force receiving surface 10150 s.

Referring to FIG. 55, the structure of the coupling will be described.

An inner surface 10150 p and a spherical surface 10153 b of adevelopment shaft 10153 of the coupling 10150 are in engagement witheach other. An urging member 10634 is interposed between an urging forcereceiving surface 10150 s described in the foregoing and a bottomsurface 10151 b of a development flange 10151. By this, the coupling10150 is urged toward the drive shaft 180 when the rotary C is stoppedat the predetermined position. In addition, similarly to the foregoingembodiments, a retention rib (unshown) is provided adjacent to the driveshaft 180 on the flange portion 10150 j with respect to the direction ofthe axis L1. By this, the disengagement of the coupling 10150 from thecartridge is prevented. The inner surface 10150 p of the coupling 10150is cylindrical. Therefore, the coupling is mounted to the cartridge B soas to be movable in the direction of the axis L2.

FIG. 56 is for illustrating the orientation of the coupling in the casethat the coupling engages with the drive shaft. FIG. 56 (a) is asectional view of the coupling 150 of Embodiment 1, and FIG. 56 (c) is asectional view of a coupling 10150 of the present embodiment. And, FIG.56 (b) is a sectional view before reaching the state of FIG. 56 (c) therotational direction is shown by X4 and the chain line L5 is a linedrawn in parallel with the mounting direction from the free end of thedrive shaft 180.

In order for the coupling to engage with the drive shaft 180, thedownstream free end position 10150A1 with respect to the rotational X4direction needs to pass the free end portion 180 b 3 of the drive shaft180. In the case of Embodiment 1, the axis L2 inclines by more thanangle α104. By this, the coupling moves to the position where the freeend position 150A1 does not interfere with the free end portion 180 b 3(FIG. 56 (a), pre-engagement angular position).

On the other hand, in the coupling 10150 of the present embodiment, itin the state where it does not be in engagement with the drive shaft180, the coupling 10150 takes the position nearest to the drive shaft180 by a restoring (elastic) force of an urging member (elastic member)10634. In this state, when it moves in the rotational direction X4, apart of the tapered surface 10150 r of the coupling 10150 contacts thedrive shaft (FIG. 56 (b)). At this time, the force is applied to thetapered surface 10150 r in the direction X4, and therefore, the coupling10150 is retracted in the longitudinal direction X11 by a componentforce thereof. And, the free end portion 10153 b of the developmentshaft 10153 abuts to an abutting portion 10150 t of the coupling 10150.In addition, the coupling 10150 rotates clockwisely about the center P1of the free end portion 10153 b (pre-engagement angular position) of thedevelopment shaft. By this, the downstream free end position 10150A1 ofthe coupling with respect to the rotational direction X4 passes by thefree end 180 b of the drive shaft 180 (FIG. 56 (c)). When the driveshaft 180 and the development shaft 10153 becomes substantiallyco-axial, a driving shaft receiving surface 10150 f of the coupling10150 contacts to the free end portion 180 b by the elastic force of theurging spring 10634. By this, the coupling becomes in the rotationlatency state (FIG. 55). In consideration of an amount of retraction ofthe coupling 10150, the degree of inclination of the axis L2 can bereduced to α106 (FIG. 56(c)).

At the time of the rotary resume the rotation in said one directionafter completion of the image forming operation, the free end portion180 b is forced on the conical shape driving shaft receiving surface10150 f of the coupling 10150 by rotation force of the rotary. Thecoupling 10150 is pivoted by this force, while retracting toward thedirection (opposite to X11 direction) of the axis L2 by this. Thecoupling 10150 is disengaged (disconnected) from the drive shaft 180.

Embodiment 9

Referring to FIG. 57, FIG. 58, and FIG. 59, embodiment 9 will bedescribed.

The present embodiment is different from Embodiment 1 in position(position of the coupling) for inputting the rotational force, andstructure for transmitting the rotational force to developing roller anddeveloper supply roller from coupling.

FIG. 57 is a perspective view of the cartridge B. In addition, FIG. 58is a perspective view illustrating a driving portion of the cartridge Bwithout the side plate. FIG. 59 (a) is a perspective view of a drivinginput gear, as seen from the driving side. FIG. 59 (b) is a perspectiveview of a driving input gear, as seen from the non-driving side.

A development gear 145 is provided to the one longitudinal end of adeveloping roller 110. In addition, a developer supply roller gear 146is provided to the one longitudinal end of the developer supply roller115 (FIG. 1). Both the gears are fixed on the roller shafts. By this,the rotational force received by the coupling 150 from the apparatusmain assembly A is transmitted to the pin (rotational force receivingportion) 155 and the gear 147. In addition, the rotational forcereceived by the gear 147 is transmitted to the developing roller 110 andthe developer supply roller 115 through the gear 145 and the gear 146.The rotational force may be transmitted to the developer stirring memberand so on. In addition, the member for transmitting the rotational forcemay not be a gear, but may be a toothed belt and so on. The drivingforce transmitting members, such as the gear or the toothed belt, areusable properly.

Referring to FIG. 59, the driving input gear 147 which mounts thecoupling 150 swingably will be described. A gear shaft 11153 is fixed bythe press-fitting, the bonding, and so on to the inside of the gear. Theend 11153 b thereof has a spherical configuration, so that it canincline smoothly when the axis L2 inclines. In this embodiment, althoughthe gear shaft 11153 is made of metal, it may be made of resin materialintegral with the gear 147. In addition, The rotational forcetransmitting pin (rotational force receiving portion) 155 for receivingthe rotational force from the coupling 150 is provided at the free endside of the gear shaft 11153, and it is extended in the directioncrossing with the axis of the gear shaft 11153.

The pin 155 is made of the metal and is fixed by the press-fitting, thebonding, and so on to the gear shaft 11153. If the transmission of therotational force is possible, the position of the pin 155 issatisfactory anywhere. Preferably, the pin 155 penetrates the sphericalsurface center of the free end portion 11153 b of the gear shaft 11153.This is because, with such a structure, even when the angle of deviationexists between the gear shaft 11153 and the axis L2, the rotationalforce transmission radius is always constant. By this, constanttransmission of the rotational force is accomplished. The number ofrotational force transmission points may be any, and the person skilledin the art can select it properly. However, in this embodiment, thesingle pin 155 is employed from the viewpoint of assured transmission ofdriving torque, and assembling property. And, the pin 155 penetrates thecenter of the free end spherical surface 11153 b. By this, the pin 155projects in the diametrically opposite-directions from the peripheralsurface of the gear shaft 11153. In other words, the rotational force istransmitted at the two places. Here, in this embodiment, although thepin 155 is metal, it may be a product made of resin material integralwith the gear shaft 11153 and the gear 147. The gears 145, 146, and 147are helical gears.

In addition, since the mounting method of the coupling 150 is the sameas that of Embodiment 1, the description is omitted.

The gear 147 is provided with a space 147 a for receiving the coupling150 partially, so that it does not interfere with the gear 147, when thecoupling 150 swings (the movement, pivoting). The space 147 a isprovided at the center portion of the gear 147. By this, it is possibleto shorten the length of the coupling 150. Furthermore, as for themounting method of the gear 147, a hole 147 b (FIG. 59 (b)) is rotatablysupported by the supporting shaft (unshown) of the development bearing11151 (FIG. 58). In addition, the cylindrical portion 147 c is rotatablysupported by the inner surface 11157 i of the supporting member 11157.

Since the engagement, drive, and disengagement of the coupling by therotating operation of the rotary C are the same as that of Embodiment 1,the description is omitted.

The means for inclining the axis L2 to the pre-engagement angularposition just before the engagement of the coupling to the drive shaftmay employ a method of any of the embodiment 2-embodiment 5 describedheretofore.

As has been described with respect to the present embodiment, it is notnecessary to dispose the coupling 150 to the end co-axial with thedeveloping roller 110. More particularly, according to the embodimentdescribed above, the coupling 150 is provided at the position remotefrom the axis L1 of the developing roller 110 in the directionperpendicular to the axis L1 of the developing roller 110. And, in thedirection of the rotation axis L2, the rotational force transmittingsurface (rotational force transmitting portion, and the cartridge siderotational force transmitting portion) 150 h are provided in theopposite side from the rotational force receiving surface (rotationalforce receiving portion) 150 e. And, the rotational force received bythe rotational force transmitting surface 150 h is transmitted to thedeveloping roller 110 through the transmission pin 155 (rotational forcereceiving portion) and the gears 145 and 147 (driving force transmittingmember). By this, the developing roller 110 is rotated by the rotationalforce received from the main assembly A by the coupling 150.

According to this embodiment, the latitude of the design of theapparatus main assembly A and the cartridge B is improved. This isbecause, in the cartridge B, the position of the coupling can beproperly selected irrespective of the position of the developing roller110.

In addition, in the apparatus main assembly A, the position of the driveshaft 180 can be properly selected irrespective of the position of thedeveloping roller 110 in the state of the cartridge B mounted to therotary C.

This is effective in development of commercial products.

Embodiment 10

Referring to FIG. 60-FIG. 69, the tenth embodiment of the presentinvention will be described.

FIG. 60 is a perspective view of the cartridge using a coupling 12150according to the present embodiment. An outer periphery of an outsideend of a development supporting member 12157 provided in the drivingside functions as the cartridge guides 140L1, 140L2.

The developing cartridge is dismountably mounted to the rotary C bythese cartridge guides 140L1, 140L2 and cartridge guide (unshown)provided in the non-driving side.

In this embodiment, the coupling can be integrally handled with thedevelopment shaft end member. Here, the development shaft end member isthe member mounted to the end of the developing roller, and it has thefunction of transmitting the rotational force to the other member in thecartridge B.

FIG. 61 (a) is a perspective view of the coupling, as seen from thedriving side. It is a perspective view, as seen from the developingroller side of FIG. 61 (b) coupling. FIG. 61 (c) is a side view of thecoupling as seen in the direction perpendicular to the direction of theaxis L2. In addition, FIG. 61 (d) is a side view of the coupling, asseen from the driving side. FIG. 61 (e) shows a view of the coupling, asseen from the developing roller side. In addition, FIG. 61 (f) is asectional view taken along a line S21-S21 of FIG. 61 (d).

The coupling 12150 of the present embodiment is engaged with the driveshaft 180 similarly to the coupling 150. To receive the rotational forcefor rotating the developing roller. In addition, it is disengaged fromthe drive shaft 180.

The coupling side driven portion 12150 a of the present embodiment hasthe function and structure similar to those of the member 150 a, and thecoupling side driving portion 12150 b has the function and structuresimilar to the member 150 b. In this embodiment, the driving portion12150 b has the spherical driving shaft receiving surface 12150 i so asto be able to move among said three angular positions irrespective ofthe rotation phase of the developing roller 110 (FIG. 61 (a), (b), (c),(f)).

In addition, the intermediate part 12150 c has the function andstructure similar to those of the member 150 c. In addition, thematerial and so on is the same as that of the member.

In addition, the opening 12150 m has the function and structure similarto those of the member 150 m (FIG. 61 (f)).

In addition, the projection 12150 d (12150 d 1-d 4) has the function andstructure similar to those of the element 150 d (FIG. 61 (a), (b), (c),(d)).

The entrance portion 12150 k (12150 k 1-k 4) has the function andstructure similar to those of the element 150 k (FIG. 61 (a), (b), (c),(d)).

In addition, the driving portion 12150 b has the spherical surface sothat, it can move between rotational force transmitting angular positionand pre-engagement angular position (or disengaging angular position)relative to the axis L1 irrespective of the rotation phase of thedeveloping roller 110 in the cartridge B5. In the illustrated example,the driving portion 12150 b has a spherical retaining portion 12150 iconcentric with the axis L2. A fixing hole 12150 g penetrated by atransmission pin 12155 at a position passing through the center of thedriving portion 12150 b is provided.

In this embodiment, the coupling 12150 comprises a driven portion 12150a, an intermediate part 12150 c, and a driving portion 12150 b. Theconnection method between them will be described in the drum flangeassembly process hereinafter.

Referring to FIG. 62, an example of a development shaft end member 12151which supports the coupling 12150 will be described. FIG. 62 (a) shows aview, as seen from the drive shaft side, and FIG. 62 (b) is a sectionalview taken along a line S22-S22 in FIG. 62 (a).

The opening 12151 g 1 or 12151 g 2 shown in FIG. 62 (a) forms a grooveextended in a rotational axis direction of a development shaft endmember 12151. At the time of mounting the coupling 12150, the rotationalforce transmitting pin (rotational force transmitting portion) 12155enters this opening 12151 g 1 or 12151 g 2.

The transmission pin 12155 moves inside of the opening 12151 g 1 or12151 g 2. By this, irrespective of the rotation phase of the developingroller 110 in the cartridge B5, the coupling 12150 is movable betweensaid three angular positions.

In addition, in FIG. 62 (a), rotational force receiving surfaces(rotational force receiving portions) 12151 h (12151 h 1 or 12151 h 2)are provided in the clockwise upstream of the opening 12151 g 1 or 12151g 2. A side of the transmission pin 12155 of the coupling 12150 contactsto the transmitting surface 12151 h. By this, the rotational force istransmitted to the developing roller 110. The transmitting surfaces12151 h 1-12151 h 2 have the surfaces intersected by the rotationaldirection of the end member 12151. By this, the transmitting surface12151 h is pressed to the side of the transmission pin 12155, androtates about the axis L1 (FIG. 62b ).

As shown in FIG. 62 (b), the end member 12151 is provided with acoupling containing section 12151 j for accommodating the drivetransmitting portion 12150 b of the coupling 12150.

FIG. 62 (c) is a sectional view illustrating the step of assembling thecoupling 12150.

As for the driven portion 12150 a and the intermediate part 12150 c ofthe coupling, the retaining member 12156 is inserted into theintermediate part 12150 c. And, the driven portion 12150 a and theintermediate part 12150 c are capped in the direction of the arrow X32by a positioning member 12150 q (a driving portion 12150 b) which has aretaining portion 12150 i. The pin 12155 penetrates the fixing hole12150 g of the positioning member 12150 q, and the fixing hole 12150 rof the intermediate part 12150 c. And, the pin 12155 fixes thepositioning member 12150 q to the intermediate part 12150 c.

FIG. 62 (d) is a sectional view illustrating the step of fixing thecoupling 12150 to the end member 12151.

The coupling 12150 is moved in the X33 direction, and the transmissionpart 12150 b is inserted in the accommodating portion 12151 j. Theretaining member 12156 is inserted in the direction of an arrow X33 tofix it to the end member 12151. The retaining member 12156 is fixed withplay to the positioning member 12150 q. By this, the coupling 12150 canchange the orientation. In this manner, a coupling unit which has thecoupling and the end member 12151 integrally is provided.

The retaining portion 12156 i mounts the coupling 12150 so that it ismovable (pivotable) between the rotational force transmitting angularposition, the pre-engagement angular position, and the disengagingangular position. In addition, the retaining portion 12156 i regulatesthe movement of the coupling 12150 in the direction of the axis L2. Inother words, the opening 12156 j has diameter phi D15 smaller than thediameter of the retaining portion 12150 i.

Similarly to the projection 12150 d, the rotational force transmittingsurfaces (rotational force transmitting portions) 12150 h 1 or 12150 h 2are preferably disposed diametrically opposed on the same circumference.

The coupling and the end member can be integrally treated by thestructure as described above. By this, the handling at the time of theassembly is easy, and the improvement of the assembling property can beaccomplished.

Referring to FIG. 63 and FIG. 64, the mounting of the cartridge B willbe described. FIG. 63 (a) is a perspective view of the major part of thecartridge, as seen from the driving side, and FIG. 63 (b) is aperspective view thereof, as seen from the non-driving side. Inaddition, FIG. 64 is a sectional view taken along a line S23-S23 in FIG.63 (a). The developing roller 110 is rotatably mounted on the developingdevice frame 119.

In the description described above, the coupling 12150 and the endmember 12151 are assembled to the coupling unit. And, the unit U10 ismounted to the development shaft 12153 by the side of the end of thedeveloping roller 110 so that the transmission part 12150 a is exposed.And, the transmission part 12150 a is assembled through an inner space12157 b of the supporting member 12157. By this, the transmission part12150 a is exposed through the cartridge.

As shown in FIG. 64, a positioning portion for the developing roller12110 12157 e is provided on the supporting member 12157. By this, theend member 12151 is retained assuredly.

Here, as shown in FIG. 66, the axis L2 of the coupling 12150 can inclinein any directions relative to the axis L1. FIG. 66(a 1)-(a 5) is a view,as seen from the drive shaft (180) side, and FIG. 66(b 1)-(b 5) is theperspective view thereof. In FIG. 66 (a 1) (b 1), the axis L2 isco-axial with the axis L1. FIG. 65 (a 2) (b 2) illustrates the coupling12150 in the upward inclined state from this state. While the couplinginclines toward the position of the opening 12151 g, the transmissionpin 12155 is moved along the opening 12151 g (FIG. 66 (a 2) (b 2)). As aresult, the coupling 12150 is inclined about the axis AX perpendicularto the opening 12151 g.

In FIG. 66 (a 3) (b 3), the coupling 12150 is inclined rightward. Thus,when the coupling inclines in the orthogonal direction of the opening12151 g, the pin 12155 rotates inside of the opening 12151 g. The axisof rotation is the axis line AY of the transmission pin 12155.

The coupling 12150 inclined downward and the coupling inclined leftwardare shown in FIGS. 66 (a 4) (b 4) and 66 (a 5) (b 5). The coupling 12150is inclined about the rotation axis AX, AY.

With respect to the direction different from the inclining direction,and in the midrange, the rotation of the circumference of the axis AXand the rotation of the circumference of AY can combine with each other,so that the inclination is permitted. For example, the directionsdifferent from the inclining direction are FIGS. 66 (a 2), (a 3), (a 3),(a 4), (a 4), (a 5), (a 5), and (a 2). In this manner, the axis L2 canbe inclined in any directions relative to the axis L1.

-   -   However, the axis L2 does not need to be necessarily pivotable        relative to the axis L1 linearly to the predetermined angle in        any directions over 360 degrees. In that case, for example, the        opening 12151 g is set slightly wide in the circumferential        direction. By such the setting, when the axis L2 inclines        relative to the axis L1, the coupling 12150 rotates to a slight        degree about the axis L2, even if it is the case where it cannot        incline to the predetermined angle linearly. By this, the axis        L2 can be inclined to the predetermined angle relative to the        axis L1. In other words, the play in the rotational direction of        the opening 150 g can be selected properly by one skilled in the        art.

As has been described hereinbefore, (FIG. 64), the spherical surface12150 i contacts to the retaining portion 12156 i. For this reason, therotation axis of the coupling 12150 is on the center P2 of the sphericalsurface 12150 i. In other words, the axis L2 is pivotable irrespectiveof the phase of the end member 12151. In addition, as will be describedhereinafter, in order for the coupling 12150 to engage with the driveshaft 180, the axis L2 is inclined to the downstream in the rotationaldirection X4 relative to the axis L1 just before the engagement. Inother words, as shown in FIG. 67, the axis L2 inclines relative to theaxis L1, so that the driven portion 12150 a is the downstream withrespect to the rotational direction X4.

FIG. 60 shows the state where the axis L2 is inclined relative to theaxis L1. In addition, FIG. 65 is a sectional view taken along a lineS24-S24 in FIG. 60.

By the structure described heretofore, the axis L2 in the inclined stateshown in FIG. 65 can also become substantially parallel with the axisL1. In addition, the maximum possible inclination angle alpha 4 (FIG.65) between the axis L1 and the axis L2 is determined so that the rangeto the position where the driven portion 12150 a and the intermediatepart 12150 c contact to the end member 12151 or the supporting member12157 is covered. And, the angle alpha 4 is set to the value requiredfor the mounting and demounting to the apparatus main assembly.

Here, in the case of the present embodiment, the maximum possibleinclination angle alpha 4 is 20 degrees-80 degrees.

As has been described with respect to Embodiment 1, immediately beforeCartridge B (B5) is determined to the predetermined position of theapparatus main assembly A, or, substantially simultaneously with itbeing determined to the predetermined position, the coupling 12150 andthe drive shaft 180 engage with each other. More particularly, thecoupling 12150 and the drive shaft 180 are engaged with each otherimmediately before or substantially simultaneously with the stoppage ofthe rotary C.

Referring to FIG. 67, the engaging operation of this coupling 12150 willbe described. FIG. 67 is a longitudinal sectional view of the apparatusmain assembly A, as seen from the lower part.

In the moving process of the cartridge B7 by the rotary C, the axis L2of the coupling 12150 inclines beforehand in the pre-engagement angularposition to the rotational direction X4 relative to the axis L1 (FIG. 67(a)). In the direction of the axis L1, the downstream free end position12150A1 with respect to the rotational direction X4 is positioned in thedeveloping roller 12110 direction side beyond the drive shaft free-end180 b 3 by the inclination of the coupling 12150. In addition, theupstream free end position 12150A2 with respect to the rotationaldirection X4 is positioned in the pin 182 direction side than the driveshaft free-end 180 b 3 (FIG. 67 (a)).

First, the upstream free end position 12150A1 with respect to therotational direction X4 of the coupling 12150 passes by the drive shaftfree-end 180 b 3. A part of coupling (receiving surface 12150 f and/orprojection 12150 d) which is the cartridge side contact portion contactsto the main assembly side engaging portion (the drive shaft 180 and/orthe pin 182), after the passage. The coupling is inclined so that theaxis L2 becomes parallel to the axis L1 in response to the rotation ofthe rotary C (FIG. 67 (c)). And, when the developing cartridge B7finally stops at the predetermined position (developing position) in theapparatus main assembly A (stoppage of the rotation of the rotary), thedrive shaft 180 and the developing roller 12110 will becomesubstantially co-axial with each other. And, the coupling 12150 is movedfrom the pre-engagement angular position toward the rotational forcetransmitting angular position where the axis L2 is substantiallyco-axial with the axis L1. And, the coupling 12150 and the drive shaft180 are engaged with each other (FIG. 67 (d)). The recess 12150 z of thecoupling covers the free end portion 180 b.

As has been described hereinbefore, the coupling 12150 is mounted forinclining motion relative to the axis L1. More particularly, thecoupling 12150 inclines without interfering with the drive shaft 180 inresponse to the rotating operation of the rotary C. By this, thecoupling 12150 can be engaged with the drive shaft 180.

Similarly to embodiment 1, the engaging operation of the coupling 12150described above can be carried out irrespective of the phase of thedrive shaft 180 and the coupling 12150.

In this manner, in this embodiment, the coupling 12150 is mounted to thecartridge B7 for substantial revolvement relative to the developingroller 110.

Referring to FIG. 68, the rotational force transmitting operation at thetime of rotating the developing roller 110 will be described. The driveshaft 180 rotates with the gear (helical gear) 181 in the direction ofX8 in the Figure by the rotational force received from the motor 64(driving source). The transmission pin 182 integral with the drive shaft180 contacts to two of the four rotational force receiving surfaces 150e of the coupling 12150 to rotate the coupling 12150. Furthermore, asstated in the foregoing, the coupling 12150 is coupled with thedeveloping roller 110 for drive transmission. For this reason, therotation of the coupling 12150 rotates the developing roller 110 throughthe end member 12151.

In addition, even if the axis L3 and the axis L1 deviate from theco-axial relations somewhat, the coupling can rotate without applyingthe large load to the developing roller and the drive shaft because thecoupling 12150 inclines slightly.

This is one of the remarkable effects according to an embodiment of thecoupling of the present invention.

Referring to FIG. 69, the description will be made as to operation ofthe coupling 12150 and so on at the time of the cartridge B (B7) movingto another station by the rotation of the rotary C. FIG. 69 is alongitudinal sectional view of the apparatus main assembly A, as seenfrom the lower part. First, similarly to embodiment 1, whenever thecartridge B moves from the position (developing position) where opposesto the photosensitive drum, the pin 182 is positioned at any two of theentrance portions 12150 k 1-12150 k 4 (FIG. 61).

In the state where the rotary C is at rest at the developing position,the axis L2 of the coupling 12150 is substantially co-axial relative tothe axis L1 (rotational force transmitting angular position). When therotary C further starts the rotation to one direction after terminationof the development, The upstream receiving surface 12150 f with respectto the rotational direction X4 and/or the projection 12150 d of thecoupling 12150 contact to free end portion 180 b of the drive shaft 180,and/or the pin 182 (FIG. 69a ), in response to the movement in therotational direction X4 of the cartridge B (developing roller 110). And,the axis L2 begins (FIG. 69b ) to incline toward the upstream in therotational direction X4. The inclining direction (pre-engagement angularposition) of the coupling at the time of the cartridge B moving thisdirection to the developing position is the substantially oppositerelative to the axis L1. By the rotating operation of this rotary C, theupstream free end portion 12150A2 with respect to the rotationaldirection X4 moves, while it is in contact with the drive shaft 180(free end portion 180 b). The axis L2 of the coupling 12150 inclines tothe position (disengaging angular position) where the upstream free endportion 150A2 reaches to the drive shaft free-end 180 b 3 (FIG. 69c ).And, in this state, the coupling 12150 is passed while it is in contactwith the drive shaft free-end 180 b 3 (FIG. 69d ). Thereafter, thecartridge B is completely retracted from the developing position by therotating operation of the rotary C.

As has been described hereinbefore, the coupling 12150 is mounted forinclining motion relative to the axis L1 to the cartridge B. And, thecoupling 12150 is inclined without interfering with the drive shaft inresponse to the rotational movement of the rotary C. By this, thecoupling 12150 can be disengaged from the drive shaft 180.

The coupling 12150 can be integrally handled with the end members (gearand so on) by the structure as described above. For this reason, theassembly operation property is improved.

The structure for inclining the axis L2 of the coupling to thepre-engagement angular position, immediately before the coupling engageswith the drive shaft may employ any of the embodiment 2-embodiment 5.

Embodiment 11

Referring to FIG. 70, FIG. 71, and FIG. 72, embodiment 11 will bedescribed.

The present embodiment is different from Embodiment 10 in the position(position of the coupling) which inputs the drive, and the structurewhich transmits the rotational force to the developing roller and thedeveloper supply roller from the coupling.

FIG. 70 is a perspective view of a cartridge according to the presentembodiment. FIG. 71 is a perspective view illustrating a driving portionof the cartridge. FIG. 72 (a) is a perspective view of a driving inputgear, as seen from the driving side. FIG. 72 (b) is a perspective viewof the driving input gear, as seen from the non-driving side.

The development gear 145 and the feed roller gear 146 are disposed atthe drive lateral end portions of the developing roller 110 and the feedroller 115 (FIG. 1), respectively. The gears 145 and 146 are fixed tothe shaft. The rotational force received by the coupling 13150 from theapparatus main assembly A is transmitted through the gear to the otherrotating members (the developing roller 110, the developer supply roller115, the toner stirring (unshown), and so on) of cartridge B (B6).

A driving input gear 13147 which supports the coupling 13150 will bedescribed.

As shown in FIG. 71, the gear 13147 is rotatably provided at theposition for engagement with the development gear 145 and the feedroller gear 146. The gear 13147 has the coupling containing section13147 j similar to the end member 12151 described in Embodiment 10 (FIG.72 (a)). The coupling 13150 is pivotably retained by a retaining member13156 on the gear 13147.

Further, the supporting member 13157 and the inclination regulationmember 13157 i are mounted to the cartridge B (FIG. 70).

The supporting member 13157 is provided with the hole and the innersurface 13157 i thereof engages with the gear 13147. Since theengagement, drive, and disengagement of the coupling by the rotatingoperation of the rotary are the same as that of Embodiment 10, thedescription is omitted for simplicity.

In addition, The structure for inclining the axis L2 of the coupling tothe pre-engagement angular position, immediately before the couplingengages with the drive shaft may employ any of that of the embodiment2-embodiment 5.

As has been described hereinbefore, it is not necessary to dispose thecoupling at the end co-axial with the developing roller. According tothis embodiment, the latitude in the design of the image forming devicebody and the cartridge can be improved. According to this embodiment,the effects similar to Embodiment 9 are provided.

Embodiment 12

Embodiment 12 will be described with reference to FIGS. 73 and 74.

In the above-described Embodiments, the case of using the rotationselecting mechanism (rotary) as the moving member for the developingdevice (cartridge B) is described. In this embodiment, another movingmember will be described.

FIGS. 73(a) and 73(b) are sectional views showing a cartridge supportingmember for supporting four cartridges B (14B1 to 14B4). FIGS. 74(a) to74(e) are perspective views and side views showing processes forengaging and disengaging a coupling with respect to a driving shaft.

Referring to FIGS. 73(a) and 73(b), the respective cartridges B (14B1 to14B4) are laterally arranged in cross section in a cartridge supportingmember 14190 and are detachably mounted to the cartridge supportingmember 14190. FIG. 73(a) is a schematic view showing a state in which afirst color cartridge 14B1 is located at a portion opposite to aphotosensitive drum 107 and is capable of performing development withrespect to the photosensitive drum 107. When the cartridge 14B1completes the development, the supporting member 14190 moves in an X20direction, so that an adjacent (second) color cartridge 14B2 is locatedat the opposing portion (developing position) with respect to thephotosensitive drum 107. Incidentally, a developer image formed on thephotosensitive drum 107 is transferred onto a transfer belt 104 a. Theseoperations are repeated for each of the colors. Finally, as shown inFIG. 73(b), a fourth color cartridge 14B4 is moved to the opposingportion with respect to the photosensitive drum 107, so that four colordeveloper images are transferred onto the transfer belt. Then, thedeveloper images are transferred from the transfer belt onto a recordingmaterial S and are fixed on the recording material S.

Incidentally, each of the cartridges 14 is moved in a directionsubstantially perpendicular to a direction of the axial line L3 of thedriving shaft 180 by the movement of the supporting member 14190 in onedirection.

As a result, a color image is formed on the recording material S.

When a series of the color image formation is completed, the supportingmember 14190 is moved in the X21 direction to be returned to an initialposition (the state of FIG. 73(a)).

Next, with reference to FIGS. 74(a) to 74(e), steps of connecting anddisconnecting the coupling with respect to the driving shaft by themovement of the supporting member will be described. Representatively,connection and disconnection of the cartridge 14B3 with respect to acoupling 14150C will be described. FIG. 74(a) is a perspective viewshowing a state of the coupling 14150C immediately before connection tothe driving shaft 180 and FIG. 74(b) is a side view thereof. FIG. 74(c)is a perspective view showing a state in which the coupling is connectedto the driving shaft and placed in a driving force transmittablecondition. FIG. 74(d) is a perspective view showing a disconnected stateof the coupling from the driving shaft and FIG. 74(e) is a side viewthereof.

In this embodiment, as a means for including the axial line L2, theconstitution described in Embodiment 5 is used. That is, a regulationrib 14191 provided to the apparatus main assembly is disposed along alower side of a line L20 through which a coupling 14150C passes andupstream from the driving shaft 180 with respect to a movement directionX20. Further, similarly as in Embodiment 6, a distance between a topsurface 14191 a of the regulation rib and the coupling 14150C is set tobe smaller when the coupling 14150C comes closer to the driving shaft180. Further, as shown in FIG. 74(b), an inclination direction of anaxial line L is regulated so that a driven portion (portion to bedriven) 14150Ca is directed upwardly with respect to the line L20 (theinclination direction is indicated by a line L30).

Here, when development with the cartridge 14B2 is completed, thesupporting member is horizontally moved in one direction. By thismovement, the cartridge 14B3 is moved toward a predetermined position.During its process, an intermediate portion 14150Cc contacts the topsurface 14191 a. At this time, as described in Embodiment 6, the drivenportion 14150Ca is directed toward the driving shaft 180 (thepre-engagement angular position) (the state of FIG. 74(a)). Thereafter,similarly as in the above-mentioned description, the coupling 14150Cengages with the driving shaft 180 (the rotating force transmittingangular position) (the state of FIG. 74(c)). Then, when image formationwith the cartridge 14B3 is completed, the cartridge 14B3 is moved in theX20 direction. The coupling 14150C is disengaged from the driving shaft180 (disengagement angular position) (the state of FIG. 74(d)). Detailsare the same as those described above, thus being omitted.

As described above, the developments with all the couplings arecompleted, the supporting member 14190 is returned to the initialposition (the state of FIG. 74(b)). An operation during a processthereof will be described. The coupling of each of the cartridges isrequired to pass through the driving shaft 180. For this reason, thecoupling is, similarly as during the development, moved from thepre-engagement angular position to the disengagement angular positionthrough the rotating force transmitting angular position. For thispurpose, it is necessary to employ a constitution for inclining theaxial line L2. As shown in FIG. 74(d), a regulation rib 14192 similar tothat descried in Embodiment 6 is disposed along the upper side of theline L20 through which the coupling 14150C passes. The rib 14192 isdisposed upstream from the driving shaft 180 with respect to themovement direction X21. Further, the distance between the regulation rib14192 and the line L20 is set similarly as in the case of the regulationrib 14192. That is, the regulation rib 14191 and the regulation rib14192 are set in a point-symmetry relationship with respect to thecenter of the driving shaft 180. Incidentally, as shown in FIG. 74(e), aregulation direction of the coupling 14150C is not changed. For thisreason, the coupling 14150C is also moved, at the initial stage (X21direction), from the pre-engagement angular position to thedisengagement angular position through the rotating force transmittingangular position by the same operation as during the image formation(development) (during the movement in the X20 direction). During thisoperation, the coupling 14150C passes through the driving shaft 180 andthen is returned to the initial position.

In this embodiment, the cartridge is detachably supported with respectto the image forming apparatus. During replacement of the cartridge, asshown in FIG. 74(a), the supporting member 14190 is rotationally movedin the X30 direction. By this rotational movement, the user moves eachof the cartridges 14B1 to 14B4 to a replaceable position.

Incidentally, in this embodiment, the movement direction of thedeveloping cartridge is obliquely upward but may also be an oppositedirection and the developing cartridge may be disposed so as to bemovable in other directions.

In the foregoing description, the image formation (development) iseffected when the cartridge is moved in one direction but is noteffected when the cartridge is moved other directions. However, thepresent invention is not limited thereto. For example, when thecartridge is moved in other directions, the image formation may beeffected.

Embodiment 13

Embodiment 13 will be described with reference to FIG. 75.

In the foregoing description, the cartridge detachably mountable theapparatus main assembly A is described. In this embodiment, such animage forming apparatus that the developing device as the developingapparatus is fixed to an apparatus main assembly and image formation iseffected by real time supply of the developer. That is, the developingdevice in this embodiment is mounted to the apparatus main assembly A bythe user but is not demounted. The developing device in this embodimentis a fixed-type in which the developing device is fixed to the apparatusmain assembly A and is used in a fixed state. Maintenance is performedby a service person.

FIG. 75 is a sectional view of the apparatus main assembly.

As shown in FIG. 75, a rotary C2 includes four color developing devices15A, 15B, 15C and 15D mounted therein. The rotary C2 further includesdeveloper bottles 16A, 16B, 16C and 16D each for supplying a developerto an associated developing device. These bottles 16A, 16B, 16C and 16Dare detachably mounted to the apparatus main assembly A in a directionperpendicular to the drawing. When the developer in the bottle empties,the bottle is replaced by the user.

By the rotation of the rotary C, each of the developing devices 15A,15B, 15C and 15D is successively moved to a portion (developingposition) opposite to the photosensitive drum 107 and at the opposingportion, a latent image formed on the photosensitive drum 107 isdeveloped. Depending on the movement of each of the developing devicesto the opposing portion, the coupling member (not shown) provided to thedeveloping device is engaged with the driving shaft provided to theapparatus main assembly (not shown). Thereafter, when the imageformation is completed, the cartridge (not shown) is disengaged from thedriving shaft. This operation is similar to that in Embodiment 1 and thelike, so that description thereof is omitted.

As described above, even in the case of drive switching of thedeveloping device fixed to the apparatus main assembly, the operationcan be performed similarly as in the cases of Embodiments describedabove.

Embodiment 14

Referring to FIG. 76, FIG. 77, and FIG. 78, embodiment 14 will bedescribed.

These embodiments differ from Embodiment 11 in the configuration of thecoupling, and provision of the elastic material for maintaining thecoupling at the pre-engagement angular position.

FIG. 76 (a) is a perspective view illustrating a part of cartridge B.FIGS. 76 (b) and FIG. 76 (a) are sectional views taken along a lineextended in the inclining direction of the axis of the coupling throughthe center of the driving input gear (the member which mounts thedriving input gear is also illustrated). FIG. 77 (a) is a side view ofthe coupling alone. FIG. 77 (b) is a perspective view of the couplingalone. FIG. 78 (a) is a sectional view illustrating the state where thecoupling (cartridge) is positioned at the pre-engagement angularposition. FIG. 78 (b) is a sectional view illustrating the state wherethe coupling (cartridge) is positioned at the rotational forcetransmitting angular position. FIG. 78 (c) is a sectional viewillustrating the state where the coupling (cartridge) is positioned atthe disengaging angular position. FIGS. 78 (a), (b), and (c) illustratethe positional relations between the coupling 15150 and the drive shaft180.

As shown in FIG. 76, the development gear 145 is disposed to the end ofthe developing roller 110. And, the gear 145 is fixed to the shaft 155of the developing roller 110.

A driving input gear 15147 which mounts the coupling 15150 will bedescribed.

As shown in FIG. 76, the gear 15147 has the gear portion for meshingengagement with the development gear 145 15147 a, and the gear portion15147 b for meshing engagement with the feed roller gear 146 (FIG. 58).And, the gear 15147 is rotatably mounted to the cartridge B by asupporting member 15170 and a supporting member 15157. The supportingmember 15170 functions also as the bearing member for the developingroller 110.

By this, the rotational force received by the coupling 15150 from theapparatus main assembly A is transmitted to the developing roller 110through the pin 15155 (rotational force transmitting portion), therotational force transmitting surface 12151 h (FIG. 62 (a), (b),rotational force receiving portion), the gear 147, and gear 145.

The coupling 15150 is pivotably mounted to the gear 15147 by a retainingportion 15147 m (movable among said three angular positions). Inaddition, the coupling 15150 is urged by an urging spring (elasticmaterial) 15159 in order to maintain the pre-engagement angularposition. In this embodiment, the spring 15159 is a torsion coil spring.A supporting portion 15159 a of the spring 15159 is locked by a mountingportion (unshown) provided on the cartridge B. And, an arm portion 15159b thereof elastically urges an intermediate part 15150 c of thecoupling. By this, the axis L2 of the coupling 15150 is maintained atthe pre-engagement angular position (FIG. 78 (a)). In the presentembodiment, a spring force (elastic force) of the spring 15159 is 5g-100 g. If it is below 5 g, the coupling may not incline correctly dueto the frictional force and so on. If it is more than 100 g, the contactportion of the spring may be shaved at the time of the rotation of thecoupling. However, the spring force other than this range may beemployed depending on the conditions, such as the wire diameter and thematerial of spring, and configuration and material of the coupling. Inaddition, it is not limited to the torsion coil spring.

More particularly, the spring 15159 (elastic material) elastically urgesthe coupling 15150. The elastic force thereof is such that it canmaintain the coupling 15150 at the pre-engagement angular position,while it permits moving the coupling from the pre-engagement angularposition to the rotational force transmitting angular position (FIG. 78(b)), and it permits moving the coupling 15150 from the rotational forcetransmitting angular position to the disengaging angular position (FIG.78 (c)).

This applies also to the spring (elastic material) 4159 described by theembodiment of the embodiment 3 and so on.

Further, the cartridge B has the inclination regulating portion forregulating the inclining direction of the coupling. Since this structureis the same as that of Embodiment 11, the description is omitted forsimplicity.

As shown in FIG. 77, the couplings 15150 differ from the coupling 12150described in Embodiment 10 in the configuration of the driven portion15150 a.

More particularly, an opening 15150 m of the driven portion 15150 a isprovided with the recess 15150 z and the flat portion 15150 y. Therecess 15150 z is contacted to the free end portion 180 b of the driveshaft 180 (FIG. 78 (b)). As shown in FIG. 78, when the coupling 15150reaches the rotational force transmitting angular position (FIG. 78 (b))through the pre-engagement angular position (FIG. 78 (a)), therotational force of the drive shaft 180 will be transmitted to thecoupling 15150 through the pin 182. In this embodiment, not the recess15150 z but the drive shaft 180 side is the flat portion 15150 y. Bythis, the peripheral part 182 d (FIG. 78 (a), (b), (c)) and the flatportion 15150 y of the coupling of the pin 182 can be brought close toeach other (FIG. 78 (b)).

By this, the lengths of the cartridge B and the apparatus main assemblyin the direction of the axis L1, L3 can be shortened. Therefore, thecartridge B and the apparatus main assembly can be downsized.

Here, an inner diameter Z1=phi of the flat portion 15150 y of thecoupling used by this implementation is about 5 mm. In addition, anouter diameter Z2=phi thereof is approx. 11 mm. In addition, a depthZ3=of the flat portion is approx. 0.6 mm. In addition, a depth of therecess 15150 z of conical shape is approx. 1.5 mm in the top part ofconical shape, and the diameter thereof is approx. 5 mm. In addition, aweight of the coupling 15150 is approx. 1.5 g. In this embodiment, thematerial of the coupling is polyacetal. However, the values of the sizeand weight are not inevitable, and the person skilled in the art canselect them properly.

In addition, in the present embodiment, the projection 15150 d (15150 d1, d 2) of the coupling is disposed at each of two places. By this, thewidth measured along the circumference of the entrance portion 150 k(150 k 1, k 2) can be enlarged. Therefore, the entrance of the pin 182to the entrance portion 150 k can be smoothed. Although the number ofthe projections can be selected properly, a plurality of projections aredesirable. This is because the rotational force can be transmitted withhigh precision.

Since the configuration of the coupling other than these and engagement,drive, and disengagement of the coupling by the rotating operation ofthe rotary are the same as that of those of Embodiment 10, thedescription is omitted for simplicity.

In addition, the structure for inclining the axis of the coupling to thepre-engagement angular position may employ any of the embodiment2-embodiment 5.

In addition, in this embodiment, the coupling 15150 is provided at theposition remote from the axis L1 in the direction perpendicular to theaxis L1 (FIG. 76 (b)).

In this embodiment, the coupling is disposed at such a position. Forthis reason, the latitude in the design of the apparatus main assemblyand the cartridge can be improved. When the coupling is disposedco-axially with the axis L1, the position of the coupling will approachthe photosensitive drum. For this reason, it is a constraint to thedisposition of the coupling, but in the present embodiment, theconstraint from the photosensitive drum is mitigable.

As has been described hereinbefore, in this embodiment, the coupling15150 has a circular flat portion 15150 y in the free end side. A recess15150 z is provided in the center O of the flat portion 15150 y(circular). The recess 15150 z has a conical shape which expands towardthe free end side thereof. In addition, projections (rotational forcereceiving portions) 15150 d are disposed at the edge of the circularflat portion 15150 y in the position diametrically opposed interposingthe center O (two positions). These projections project in the directionof the rotation axis L2 of the coupling. In addition, the pins(rotational force applying portions) 182 project in the directionsperpendicular to the axis L3. (τ) to provide the projections at the twoplaces opposed to each other, respectively. Any one of the rotationalforce receiving surfaces (rotational force receiving portions) 15150 eengages with one of the pin projections 182. And, the other one of therotational force receiving surfaces 15150 e engages with the other oneof the pin projections 182. By this, from the drive shaft 180, thecoupling 15150 receives the rotational force and rotates.

Here, according to the embodiments described above, in the structure ofmoving the cartridge B (developing roller 110) in the directionsubstantially perpendicular to the direction of the axis L3 of the driveshaft 180 in response to in the movement to the one direction of therotary C (supporting member 14190), the coupling 150 (1350, 3150, 4150,5150, 7150, 8150, 9150, 10150, 12150, 13150, 15150 and so on) canaccomplish the coupling, the engagement, and the disengaging operationrelative to the drive shaft 180. This is accomplished because thiscoupling can take the next positions as described above: 1. Therotational force transmitting angular position for transmitting therotational force from the apparatus main assembly A to the developingroller 110; 2. this pre-engagement angular position inclined from thisrotational force transmitting angular position before this couplingengages with the rotational force applying portion and; 3. Thedisengaging angular position inclined toward the opposite side from thepre-engagement angular position from the rotational force transmittingangular position for the coupling to disengage from drive shaft.

Here, the rotational force transmitting angular position is the angularposition of the coupling for transmitting the rotational force forrotating the developing roller 110 to the developing roller 110.

In addition, the pre-engagement angular position is the angular positionwhich is inclined from the rotational force transmitting angularposition and which is taken before the drum coupling member engages withthe rotational force applying portion.

In addition, the disengaging angular position is the angular positionwhich is inclined toward the opposite side from the pre-engagementangular position from the rotational force transmitting angular positionand which permits the disengagement of the coupling from the drive shaft180.

Here, the meaning “perpendicular substantially” will be described. Here,the description will be made about “perpendicular substantially”.Between the cartridge b and the apparatus main assembly A and in orderto mount and demount the cartridge B smoothly, small gaps are provided.More specifically and the small gaps are provided between the guide140R1 and the guide 130R1 with respect to the longitudinal direction,between the guide 140R2 and the guide 130R2 with respect to thelongitudinal direction, between the guide 140L1 and the guide 130L1 withrespect to the longitudinal direction between, and the guide 140L2 andthe guide 130L2 with respect to the longitudinal direction. Therefore,at the time of the mounting and demounting of the cartridge B relativeto the apparatus main assembly A and the whole cartridge B can slightlyincline within the limits of the gaps. For this reason and theperpendicularity is not meant strictly. However, even in such a case,the present invention is accomplished with the effects thereof.Therefore, the term “perpendicular substantially” covers the case wherethe cartridge slightly inclines.

Between the cartridge b and the cartridge accommodating portion 130A,small gaps are provided in order to mount and demount the cartridge Bsmoothly. more specifically and the small gaps are provided between theguide 140R1 or 140R2 and the guide 130R1 with respect to thelongitudinal direction, between the guide 140L1 or 140L2 and the guide130L1 with respect to the longitudinal direction. Therefore, at the timeof the mounting and demounting of the cartridge b relative to theaccommodating portion 130A and the whole cartridge B can slightlyincline within the limits of the gaps. in addition, in addition and aslight positional deviation may occur between the rotary member C(movable member) and the driving shaft. (180) for this reason, theperpendicularity is not meant strictly. however, even in such a case,the present invention is accomplished with the effects thereof.therefore, the term “perpendicular substantially” covers the case wherethe cartridge slightly inclines.

It has been described that the axis L2 is slantable or inclinable in anydirection relative to the axis L1. However, the axis L2 does notnecessarily need to be linearly slantable to the predetermined angle inthe full range of 360-degree direction in the coupling 150. For example,the opening 150 g can be selected to be slightly wider in thecircumferential direction. By doing so, the time of the axis L2inclining relative to the axis L1, even if it is the case where itcannot incline to the predetermined angle linearly, the coupling 150 canrotate to a slight degree around the axis L2. Therefore, it can beinclined to the predetermined angle. In other words, the amount of theplay in the rotational direction of the opening 150 g is selectedproperly if necessary.

In this manner, the coupling 150 is revolvable or swingable over thefull-circumference substantially relative to the axis L1 of thedeveloping roller 110. More particularly, the coupling 150 is pivotableover the full-circumference thereof substantially relative to the drumshaft 153.

Furthermore, as will be understood from the foregoing explanation, thecoupling 150 is capable of whirling in and substantially over thecircumferential direction of the drum shaft 153. Here, the whirlingmotion is not a motion with which the coupling itself rotates about theaxis L2, but the inclined axis L2 rotates about the axis L1 of thedeveloping roller although the whirling here does not preclude therotation of the coupling per se about the axis L2 of the coupling 150.

In addition, as has been described hereinbefore, each coupling has thefunction of transmitting the rotational force to the developing roller110.

And, each coupling, it has the rotational force reception surface(rotational force receiving portion) 150 e (8150 e, 9150 e, 9250 e, 9350e, 9450 e, 15150 e) for receiving the rotational force from the driveshaft 180 (1180, 1280, 9180) by engaging with the pin (rotational forceapplying portion) 182 (1182, 9182). In addition, it has the rotationalforce transmitting surface (rotational force transmitting portion) 150 h(1550 h, 1450 h, 8150 h, 9150 h, 12150 h, 12151 h, and so on) whichtransmits the rotational force received through the rotational forcereceiving portion 150 e to the developing roller 110. The rotationalforce received by the rotational force transmitting surface 150 h istransmitted to the developing roller 110 through the pin (rotationalforce receiving portion) 155 (1155, 1355, 12155).

And, this coupling moves from this pre-engagement angular position tothis rotational force transmitting angular position in response to themovement of cartridge B at the time of the rotary C (supporting member141190) (movable member) rotating in one direction (movement). By this,this coupling is opposed to this drive shaft. When the rotary C furtherrotates in said one direction from the position where the couplingopposes to the drive shaft (movement), the coupling moves from therotational force transmitting angular position to the disengagingangular position in response to the cartridge B moving. By this, thecoupling disengages from the drive shaft.

The coupling has the recess 150 z (1450 z, 1550 z, 4150 z, 515 z 0,15150 z, 15150 z, and so on) on the rotation axis L2. And, the cartridgeB moves in the direction substantially perpendicular to the axis L1 ofthe developing roller 110 by the rotation of the rotary C in said onedirection. In response to this, each coupling moves from thepre-engagement angular position to the rotational force transmittingangular position, so that a part of coupling (downstream free endposition 150A1, 1850A1, 4150A1, 5150A1, 8150A1, 12150A1 and so on) whichis the downstream portion with respect to the rotational direction ofthe rotary C is permitted to circumvent the drive shaft. By this, therecess covers the free end of the drive shaft. And, the rotational forcereceiving portion engages, in the rotational direction of the coupling,with the rotational force applying portion which projects in thedirection perpendicular to the axis of the drive shaft in the free endside of the drive shaft. By this, from the drive shaft, the couplingreceives the rotational force and rotates. And, the rotary C furthermoves to said one direction. By this, the cartridge B moves in thedirection substantially perpendicular to the axis L1. It responds tothis, the coupling is moved to the disengaging angular position, in therotational direction, from the rotational force transmitting angularposition, so that a part of upstream drive shafts of this couplingmember (upstream free end position 150A2, 1750A2, 4150A2, 5150A2,12150A2 and so on) is permitted circumventing the drive shaft. By this,the coupling disengages from the drive shaft.

The rotational force receiving portions (150 e, 15150 e, and so on) aredisposed, respectively on a phantom circle C1 which has a center O onthe rotation axis L1 of this each coupling, at the positionsdiametrically opposed interposing the center O. The forces received bythe couplings by this disposition are force couples. For this reason,the couplings can continue rotary motion only with the force couple. Inview of this, each coupling can rotate without determining the positionof the rotation axis.

The reference numerals in the drawing which do not appear in thespecification are the corresponding members in the case that thealphabets thereof are the same.

The Other Embodiments

In this embodiment, although the rotary rotates in the clockwisedirection on the drawing (FIG. 17, for example), it may rotate in theopposite direction.

In addition, the image forming position (developing position) may beanother position.

In addition, the rotary of the present embodiment carries the four colordeveloping cartridges. However, the developing cartridge for the blackmay be fixed and the cartridges for the other three colors may becarried on the rotary.

In addition, in this embodiment, the developing roller is a contactdevelopment type and uses an elastic roller, but it may be a metalsleeve which contains a magnet roller employed by the jumpingdevelopment.

The developing cartridge and the developing device are provided with thedeveloping roller (or developing means including the developing roller)at least. For this reason, for example, the developing cartridge(developing device) is the developing roller. Or, it may be a cartridgewhich includes integrally the developing means including the developingroller and the cleaning means and which is detachably mountable to theapparatus main assembly, in addition to the type in the embodimentdescribed above further, it may be a cartridge which includes integrallythe developing roller (or developing means including the developingroller) and the charging means and which is detachably mountable to theapparatus main assembly.

Further, in addition, in this embodiment, although a laser beam printeris taken as an image forming device, the present invention is notlimited to this example. For example, the present invention can be usedto the other image forming apparatuses, such as an electrophotographiccopying machine, a facsimile device, or a word processor. according tothe embodiments described above the engagement and disengagement of thecoupling are possible in the direction substantially perpendicular tothe axis of the drive shaft provided in the main assembly of theelectrophotographic image forming apparatus relative to the drive shaftby the movement in one direction of the movable member (the rotary, forexample, the cartridge supporting member, cash drawer).

As has been described hereinbefore, the axis of the coupling can takethe different angular positions in the present invention. Moreparticularly, the axis of the coupling can take the pre-engagementangular position, the rotational force transmitting angular position,and the disengaging angular position. The coupling can be engaged withthe drive shaft in the direction substantially perpendicular to the axisof the providing-in the main assembly drive shaft by this structure. Inaddition, the coupling can be disengaged from the drive shaft in thedirection substantially perpendicular to the axis of the drive shaft.The present invention can be applied to a developing device, a drumcoupling member, and an electrophotographic image forming device.

While the invention has been described with reference to the structuresdisclosed herein, it is not confined to the details set forth and thisapplication is intended to cover such modifications or changes as maycome within the purpose of the improvements or the scope of thefollowing claims.

This application claims priority from Japanese Patent Applications Nos.076771/2007 and 073685/2008 filed Mar. 23, 2007 and Mar. 21, 2008,respectively which are hereby incorporated by reference.

1. A developing device usable with an electrophotographic image formingapparatus, said apparatus including a driving shaft rotatable by a motorand having a rotating force applying portion, and a movable member, saiddeveloping device being mountable to the movable member, and saiddeveloping device being movable in a direction substantiallyperpendicular to an axial direction of the driving shaft in response tomovement of the movable member in one direction with said developingdevice mounted to the movable member, said developing device comprising:i) a developing roller for developing an electrostatic latent imageformed on an electrophotographic photosensitive drum, said developingroller being rotatable about an axis; and ii) a coupling member fortransmitting a rotating force to said developing roller, said couplingmember including, a rotating force receiving portion engageable with therotating force applying portion to receive a rotating force from thedriving shaft, and a rotating force transmitting portion fortransmitting the rotating force received through said rotating forcereceiving portion to said developing roller, said coupling member beingcapable of taking a rotational force transmitting angular position fortransmitting the rotational force for rotating said developing roller tosaid developing roller, a pre-engagement angular position which is takenbefore said coupling member is engaged with the rotating force applyingportion and in which said coupling member is inclined away from saidrotational force transmitting angular position, and a disengagingangular position which is taken for said coupling member to disengagefrom the driving shaft and in which said coupling member is inclinedaway from the rotational force transmitting angular position in adirection opposite to said pre-engagement angular position; wherein inresponse to a movement of said developing device when the movable membermoves in said one direction, said coupling member moves from thepre-engagement angular position to the rotational force transmittingangular position to be opposed to the driving shaft, and wherein whenthe movable member makes a further movement in said one direction from aposition where said coupling member is opposed to the driving shaft, inresponse to the further movement, said coupling member is disengagedfrom the driving shaft by moving from the rotational force transmittingangular position to the disengaging angular position. 2-34. (canceled)